Phenyloxazolidinones having a C-C bond to 4-8 membered heterocyclic rings

ABSTRACT

A process for preparing a compound of the formula I:or pharmaceutical acceptable salts thereof wherein X is -NR1-, -S(O)g-, or -O-; R1 is -H, C1-6 alkyl optionally substituted with one or more -OH, -CN, or halo, or R1 is -(CH2)h-aryl, -COR1-1, -COOR1-2, -CO-(CH2)h-COR1-1, C1-6 alkyl sulfonyl, -SO2-(CH2)h-aryl, or -(CO)i-Het; R2 is -H, C1-6 alkyl, -(CH2)h-aryl, or halo; R3 and R4 are the same or different and are -H or halo; R6 is -H, C1-12 alkyl optionally substituted with one or more halo, C3-12 cycloalkyl, C1-6 alkoxy. The compounds are useful antimicrobial agents.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional application of U.S. patent applicationSer. No. 08/696,313, filed Aug. 13, 1996, now U.S. Pat. No. 5,968,962,which in turn claims the benefit of the following provisionalapplication: U.S. Ser. No. 60/003,149, filed Sep. 1, 1995, under 35 USC119(e)(i).

BACKGROUND OF THE INVENTION

The present invention relates to new and useful N-phenyloxazolidinonecompounds and their preparations, and more particularly toN-phenyloxazolidinone compounds in which the phenyloxazolidinone moietyis linked to a variety of saturated, or partially saturated, 4-8membered heterocycles containing oxygen, nitrogen, and sulfur through acarbon-carbon bond.

The compounds are useful antimicrobial agents, effective against anumber of human and veterinary pathogens, including gram-positiveaerobic bacteria such as multiply-resistant staphylococci andstreptococci, as well as anaerobic organisms such as bactericides andclostridia species, and acid-fast organisms such as Mycobacteriumtuberculosis and Mycobacterium avium. The compounds are particularlyuseful because they are effective against the latter organisms which areknown to be responsible for infection in persons with AIDS.

INFORMATION DISCLOSURE

A series of Delalande patent applications (Derwent Abstracts 61219Y/35,67436R-B, 84475A/47) disclose a saturated nitrogen heterocycle linkedthrough the nitrogen atom to a phenyloxazolidinone moiety.

French Patent (FR2500450 A1 820827) discloses cyclohexenone attached atthe 3-position to a phenyloxazolidinone.

Other references disclose fully aromatic heterocycles attached to aphenyloxazolidinone, including European Patent Publication 0352 781 A2,U.S. Pat. No. 5,130,316, U.S. Pat. No. 5,254,577, U.S. Pat. No.4,948,801, and WO 9309103-A1, whereas in our present invention theheterocycle is saturated or partially saturated.

SUMMARY OF THE INVENTION

The present invention provides new compounds of the Formula (I)

or pharmaceutical acceptable salts thereof wherein:

X is

NR₁, S(O)_(g), or O;

R₁ is

a) H,

b) C₁₋₆ alkyl, optionally substituted with one or more OH, CN, or halo,

c) —(CH₂)_(h)-aryl,

d) —COR₁₋₁,

e) —COOR₁₋₂,

f) —CO—(CH₂)_(h)—COR₁₋₁,

g) —SO₂—C₁₋₆ alkyl,

h) —SO₂—(CH₂)_(h)-aryl, or

i) —(CO)_(i)-Het;

R₁₋₁ is

a) H,

b) C₁₋₆ alkyl, optionally substituted with one or more OH, CN, or halo,

c) —(CH₂)_(h)-aryl, or

d) —(CH₂)_(h)—OR₁₋₃;

R₁₋₂ is

a) C₁₋₆ alkyl, optionally substituted with one or more OH, CN, or halo,

b) —(CH₂)_(h)-aryl, or

c) —(CH₂)_(h)—OR₁₋₃;

R₁₋₃ is

a) H,

b) C₁₋₆ alkyl,

c) —(CH₂)_(h)-aryl, or

d) —CO(C₁₋₆ alkyl);

R₂ is

a) H,

b) C₁₋₆ alkyl,

c) —(CH₂)_(h)-aryl, or

d) halo;

R₃ and R₄ are the same or different and are

a) H, or

b) halo;

R₅ is

a) H,

b) C₁₋₁₂ alkyl, optionally substituted with one or more halo,

c) C₃₋₁₂ cycloalkyl,

d) C₁₋₆ alkoxy;

g is 0, 1, or 2;

h is 1, 2, 3, or 4;

i is 0 or 1;

m is 0, 1, 2, 3, 4, or 5;

n is 0, 1, 2, 3, 4, or 5;

and with the provision that m and n taken together are 1, 2, 3, 4, or 5.

More particularly, the present invention provides compounds of formula(I) wherein R₁ is H, fluoroethyl, cyanomethyl, methyl sulfonyl, formyl,hydroxyacetyl, acetyl, methoxyacetyl, benzyloxyacetyl, acetoxyacetyl,dichloroacetyl, methoxy carbonyl, tert-butoxy carbonyl, benzyloxycarbonyl, 3-hydroxypropionyl, 3-methoxypropionyl, 4-oxopentanoyl,2-indole carbonyl, 5-isoxazole carbonyl, 5-nitro-2-thiazoyl,4-oxo-2-thiazolinyl, or 5-methyl-1,2,4-thiadiazol-2-yl.

R₂ is H, F, or CH₃;

R₃ and R₄ are the same or different and are H or F; and

R₆ is methyl or methyl substituted with one or more F or Cl.

The present invention also provides a method for treating microbialinfections in patients by administering to a patient in need thereof aneffective amount of a compound of Formula (I). The compound can beadministered orally, parenterally or topically in a pharmaceuticalcomposition. Preferably, the compound is administered in an amount offrom about 0.1 to about 100 mg/kg of body weight/day.

DETAILED DESCRIPTION OF THE INVENTION

For the purpose of the present invention, the term “C₁₋₆ alkyl” and theterm “C₁₋₁₂ alkyl” refer to any straight or branched alkyl group havingone to six or one to twelve carbons respectively such as, for example,methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,t-butyl, n-pentyl, osopentyl, n-hexyl, isohexyl, n-heptyl, n-octyl andthe like.

The term “C₁₋₆ alkyl sulfonyl” refers to any straight or branched alkylgroup having one to six carbons attached to —SO₂ forming such groups as,for example, methyl sulfonyl, ethyl sulfonyl, isopropyl sulfonyl and thelike.

The term “C₃₋₁₂ cycloalkyl” refers to three to twelve carbon atomsforming cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl and the like.

The term “C₁₋₄ alkoxy” and the term “C₁₋₆ alkoxy” refer to any straightor branched alkyl group having one to four or one to six carbons,respectively, attached to an oxygen forming such groups as, for example,methoxy, ethoxy, n-propoxy, isopropoxy, n-butyloxy, isobutyloxy,sec-butyloxy, t-butyloxy, n-pentyloxy, isopentyloxy, n-hexyloxy,iso-hexyloxy and the like.

The term halo refers to fluoro, chloro, bromo, or iodo.

The term “aryl” refers to a phenyl, pyridyl or napthyl moiety which canbe optionally substituted with one or more F, Cl, Br, I, CN, OH, SH,C₁₋₆ alkyl, C₁₋₆ alkoxy, or C₁₋₆ thioalkyl.

The term “Het” refers to 5 to 10 membered heterocyclic rings containingone or more oxygen, nitrogen, and sulfur forming such groups as, forexample, pyridine, thiophene, furan, pyrazoline, pyrimidine, 2-pyridyl,3-pyridyl, 4-pyridyl, 2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl,3-pyridazinyl, 4-pyridazinyl, 3-pyrazinyl, 2-quinolyl, 3-quinolyl,1-isoquinolyl, 3-isoquinolyl, 4-isoquinolyl, 2-quinazolinyl,4-quinazolinyl, 2-quinoxalinyl, 1-phthalazinyl, 4-oxo-2-imidazolyl,2-imidazolyl, 4-imidazolyl, 3-isoxazolyl, 4-isoxazolyl, 5-isoxazolyl,3-pyrazolyl, 4-pyrazolyl, 5-pyrazolyl, 2-oxazolyl, 4-oxazolyl,4-oxo-2-oxazolyl, 5-oxazolyl, 4,5,-dihydrooxazole, 1,2,3-oxathiole,1,2,3-oxadiazole, 1,2,4-oxadiazole, 1,2,5-oxadiazole, 1,3,4-oxadiazole,2-thiazolyl, 4-thiazolyl, 5-thiazolyl, 3-isothiazole, 4-isothiazole,5-isothiazole, 2-indolyl, 3-indolyl, 3-indazolyl, 2-benzoxazolyl,2-benzothiazolyl, 2-benzimidazolyl, 2-benzofuranyl, 3-benzofuranyl,benzoisothiazole, benzisoxazole, 2-furanyl, 3-furanyl, 2-thienyl,3-thienyl, 2-pyrrolyl, 3-pyrrolyl, 3-isopyrrolyl, 4-isopyrrolyl,5-isopyrrolyl, 1,2,3,-oxathiazole-1-oxide, 1,2,4-oxadiazol-3-yl,1,2,4-oxadiazol-5-yl, 5-oxo-1,2,4-oxadiazol-3-yl, 1,2,4-thiadiazol-3-yl,1,2,4-thiadiazol-5-yl, 3-oxo-1,2,4-thiadiazol-5-yl,1,3,4-thiadiazol-5-yl, 2-oxo-1,3,4-thiadiazol-5-yl, 1,2,4-triazol-3-yl,1,2,4-triazol-5-yl, 1,2,3,4-tetrazol-5-yl, 5-oxazolyl, 1-pyrrolyl,1-pyrazolyl, 1,2,3-triazol-1-yl, 1,2,4-triazol-1-yl, 1-tetrazolyl,1-indolyl, 1-indazolyl, 2-isoindolyl, 7-oxo-2-isoindolyl, 1-pruinyl,3-isothiazolyl, 4-isothiazolyl and 5-isothiazolyl, 1,3,4-oxadiazole,4-oxo-2-thiazolinyl, or 5-methyl-1,3,4-thiadiazol-2-yl, thiazoledione,1,2,3,4-thiatriazole, 1,2,4-dithiazolone. Each of these moieties may besubstituted as appropriate.

The term “pharmaceutically acceptable salts” refers to salts useful foradministering the compounds of this invention and include hydrochloride,hydrobromide, hydroiodide, sulfate, phosphate, acetate, propionate,lactate, mesylate, maleate, malate, succinate, tartrate, citrate,2-hydroxyethyl sulfonate, fumarate and the like. These salts may be inhydrated form.

In the structural representation of Formula (I) the dotted line in theheterocyclic ring means that this bond can be either single or double.In the case where the dotted line is a double bond, the R₂ group willnot be present.

In a preferred embodiment of the N-phenyloxazolidinone compounds of thepresent invention, the X group is preferably NR₁, SO₂, or oxygen.

The R₁ substituent on the nitrogen atom can be introduced by syntheticmethods known to those skilled in the art from commercially availablereagents.

The preferred R₁ substituent is H, fluoroethyl, cyanomethyl, methylsulfonyl, formyl, hydroxyacetyl, acetyl, methoxyacetyl, benzylosyacetyl,acetoxyacetyl, dichloroacetyl, methoxy carbonyl, tert-butoxy carbonyl,benzyloxy carbonyl, 3-hydroxypropionyl, 3-methoxypropionyl,4-oxopentanoyl, 2-indole carbonyl, 5-isoxazole carbonyl,5-nitro-2-thiazolyl, 4-oxo-2-thiazolinyl, or5-methyl-1,3,4-thiadiazol-2-yl. The most preferred R₁ substituent isformyl, methoxy carbonyl, or hydroxyacetyl.

Where heterocyclic rings are the saturated derivatives, the preferred R₂substituent is hydrogen, fluoro, or methyl.

The preferred R₃ and R₄ substituents are independently hydrogen orfluoro.

The preferred R₅ substituent is methyl.

The most preferred compounds in this series would be prepared as theoptically pure enantiomers having the (S)-configuration according to theCahn-Ingold-Prelog notation at C5 of the oxazolidinone ring. Opticallypure material could be prepared by one of a number of asymmetricsyntheses. For example, treatment of intermediate compound 12 in CHART Bwith an appropriate base, followed by addition of (R)-glycidyl butyratewould afford the corresponding oxazolidinone in optically pure form withthe requisite (S)-configuration at the 5-position of the oxazolidinonering. Although the (S)-enantiomer of this series of compounds ispreferred since it is pharmacologically active as an antibacterialagent, the racemic modification is also useful in the same manner as thepure (S)-enantiomer; the difference being that twice as much racemicmaterial is required to elicit the same antibacterial effect.

CHART A illustrates methods for preparing compounds of Formula (I)having a heterocycle containing nitrogen. As shown in CHART A, the keyintermediate 1 can be used to make derivatives by reactions known tothose skilled in the art. For example, acylation affords 2 and 3, thesubsequent deprotection of 2 provides 2′, alkylation affords 5 (thesubstituents including hydroxy, nitro, halo, aryl, and sulfonyl;structure 5 also encompasses products having a heteroatomic nucleus),sulfonylation affords 6, and alkoxyacylation affords 4.

A method for preparing compounds of intermediate 1 having a 4-memberedheterocycle containing nitrogen in highly enantiomerically enriched formis depicted in CHART B. The first step involves treatment of structure 7with ethyl cyanoacetate in the presence of an appropriate base, such assodium hydride or potassium carbonate, at a temperature in the range of−10° C. to 100° C. The subsequent alkylation using alkyl halides ortosylates affords nitrile derivative 8. The nitrile derivative 8 is thenreduced by catalytic hydrogenation in the presence of an appropriatecatalyst, such as palladium on carbon, W-2 Raney nickel or platinum onsulfide carbon, in an appropriate solvent, such as ethyl acetate, THF,methanol or combinations thereof, to give amino-aniline 9, which upontreatment with an appropriate base, preferably methyl or ethyl Grignard,affords the lactam 10. Reduction of 10 by using an appropriate reducingagent, such as LAH or borane, gives the azetidine 11, which reacted withbenzyl chloroformate, at a temperature in the range of −10° C. to 10°C., affords the corresponding benzyl carbamate derivatives 12. Thetreatment of 12 with n-butyllithium in an appropriate solvent such asTHF, at a temperature in the range of −78° C. to −40° C., followed byaddition of commercially available (R)-glycidyl butyrate dropwise wouldafford the corresponding oxazolidinone 13 in enantiomerically enrichedform at the 5-position of the oxazolidinone ring. As shown in CHART B,compound 13 can be converted to the corresponding alkyl or arylsulfonate 14 by treatment with alkyl or aryl sulfonyl chloride in thepresence of triethylamine or pyridine (wherein R′ is C₁₋₄ alkyl or(un)substituted phenyl). The resultant sulfonate 14 is then treated withan alkali metal azide such as sodium or potassium azide, in an aproticdipolar solvent such as DMF or N-methylpyrrolidinone (NMP), with anoptional catalyst such as 18-crown-6, at a temperature in the range of50° C. to 90° C. to afford azide derivatives. The azide derivatives canbe reduced to the corresponding amine 15 by hydrogenation in thepresence of a palladium, platinum or nickel catalyst, in an appropriatesolvent such as ethyl acetate, THF, or methanol. Alternatively, amine 15can be prepared by treating 14 with an appropriate solvent such asmethanol and/or THF which is saturated with ammonia and heating themixture to 100° C. in a sealed tube. The reaction occurs over hours,e.g., 40-70 hours. Amine 15 is then acylated with an acid chloride oranhydride in the presence of a base such as pyridine or triethylamine attemperatures ranging from −40° C. to 40° C. to provide the N-acyloxazolidinone 16. Finally, catalytic hydrogenation of 16 in the presenceof a noble metal catalyst, such as palladium on carbon or palladiumhydroxide on carbon affords the azetidine 17. The azetidine 17 can beused to prepare derivative compounds demonstrated in CHART A.

The following compounds of Formula (I) having a 4-membered heterocyclecontaining nitrogen, for example, are prepared directly by the methodsdescribed in CHART A and CHART B:

(S)—N—[[3-[3-Fluoro-4-[1-(carbobenzyloxy)-(3-methyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(carboxymethyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]meyhyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(methoxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(formyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(dichloroacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(3-methoxypropionyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(3-hydroxypropionyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(4-oxopentanoyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-acetyl-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(2-fluoroethyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(cyanomethyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(5-nitro-2-thiazolyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(methanesulfonyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(benzyloxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(hydroxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

A second method for preparing compounds of intermediate 1 having a4-membered heterocycle containing nitrogen, wherein R₂ is H, in highlyenantiomerically enriched form is depicted in CHART C. The first stepinvolves reaction of structure 18 with a protected aniline 19 in thepresence of an appropriate base, such as sec-butyllithium, in anappropriate solvent, such as THF, at a temperature range of −40° C. to−78° C. to afford compounds 20. Reaction of 20 with benzyl chloroformateat 0° C. to 25° C. gives compound 21 which reacts further at 25° C. to100° C. to give compound 22. Treatment of 22 with excess triethylsilaneand trifluoroacetic acid in a suitable solvent such as methylenechloride, at a temperature range of 10° C. to 40° C. gives compound 23.The remaining synthetic steps which lead to structure 17 are similar tothe procedures outlined in CHART B.

The following compounds of Formula (I) having a 4-membered heterocyclecontaining nitrogen, for example, are prepared directly by the methodsdescribed in CHART A and CHART C:

(S)—N—[[3-[3-Fluoro-4-[1-(carbobenzyloxy)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(carboxymethyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N—[[3-[3-Fluoro-4-[1-(formyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

CHART D depicts a method for preparing compounds of intermediate 1having a 5-membered heterocycle containing nitrogen. As shown in CHARDD, the first step involves the coupling of vinyltributyltin 24(commercially available) and compound 25. The compound 25 can beprepared according to the procedures described in PCT/US92/08267 andPCT/US93/09589. The coupling occurs in the presence of palladiumcatalyst to afford compound 26. The reaction is carried out at a hightemperature for several hours, e.g., reflux for 5-8 hours. The compound26 is then treated with a solution ofN-benzyl-N-(methoxymethyl)trimethylsilyl-methylamine (prepared accordingto the literature from commercially available material) andtrifluoroacetic acid in an appropriate solvent to provide 27. Thereaction occurs over several hours, e.g., 8-17 hours. The N-benzyl groupof 27 is then removed by catalytic hydrogenation in the presence of anoble metal catalyst, such as palladium on carbon or palladiumhydroxideon carbon to afford 28. The compound 28 can be sued to prepare thederivative compounds demonstrated in CHART A. Following a similarprocedure and making non-critical variations but substituting differentvinyl tributylstannyl derivatives for structure 24, a variety of otherheterocyclic derivatives of compound 26 can be obtained as illustratedin EXAMPLE 80.

Alternatively, another method for preparing compounds of intermediate 1having a 5-membered heterocycle containing nitrogen is depicted in CHARTE. As shown in CHART E, nucleophilic aromatic substitution of 7 withdimethylmalonate (commercial available) affords the adduct 29. Thereaction occurs in an appropriate solvent such as THF, at a temperaturein the range of −100° C. to 60° C. The compound 29 is readily alkylatedby a reaction known to those skilled in the art to provide nitrile 30.Catalytic reduction of 30 in the presence of a palladium, platinum ornickel catalyst, in an appropriate solvent such as methanol convertsboth nitro and nitrile to amines with concommittant intramilecularcyclization to afford the lactam 31. The lactam 31 is thendecarboxylated to provide 32, which upon reduction with an appropriatereducing agent such as lithium aluminum hydride or borane, in anappropriate solvent such as THF or ether, affords compound 33. Theremaining synthetic steps which lead to structure 34 are similar to theprocedures outlined in CHART B.

The following compounds of Formula (I) having a 5-membered heterocyclecontaining nitrogen, for example, are prepared directly by the methodsdescribed in CHART A, CHART D and CHART E:

(S)—N—[[3-[3-Fluoro-4-[1-(hydroxyacetyl)-3-pyrrolidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide;

(S)—N-[[3-[3-Fluoro-4-[1-(formyl)-3-pyrrolidinyl]phenyl]2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-3-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2fluorophenyl]-1-pyrrolidinecarboxylic acid methyl ester.

Following the general procedure depicted in CHART D for the preparationof compound 26 and making non-critical variations but substituting6-(tributylstannyl)-3,4-dihydro-2H-dihydropyran for structure 24, thefollowing compound is prepared:

(S)—N-[[3-[3-Fluoro-4-(3,4-dihydro-2H-pyran-6-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide.

A method for preparing compounds of formula (I) having a 5-memberedheterocycle containing a sulfur atom, oxygen atom, sulfone group orsulfoxide group in highly enantiomerically enriched form wherein R₃ orR₄ is halo is depicted in CHART F. As shown in CHART F, structure 35(wherein X is O or S) is reacted with a protected aniline 19 in thepresence of an appropriate base, such as sec-butyllithium, in anappropriate solvent, such as THF, at a temperature range of −40° C. to−78° C. to afford compounds 36. Reaction of 36 with benzyl chloroformateat 0° C. to 25° C. gives compound 37. The subsequent eliminationreaction known to those skilled in the art affords regiosiomers 38 and39 as a mixture. Following the general procedure outlined in CHART Bprovides compounds 40 and 41 as a mixture. In the case where X is S, thesulfur group can be oxidized by an appropriate oxidizer such asN-methylmorpholine N-oxide and osmium tetroxide in an appropriatesolvent such as mixtures of water and acetone, or by NaIO₄ in anappropriate solvent such as mixtures of water and methanol, to providethe corresponding sulfones and sulfoxides, respectively. When it isdesirable, the double bond in the heterocycle ring may be reduced bycatalytic hydrogenation in the presence of an appropriate catalyst and asuitable solvent. Furthermore, in the case where X is O, SO, or SO₂, theregioisomeric mixture of 40 and 41 can be separated by chromatography asillustrated in EXAMPLEs 68 and 69.

The following compounds of Formula (I) having a 5-membered heterocyclecontaining a sulfur atom, oxygen atom, sulfone group or sulfoxide group,for example, are prepared directly by the method of CHART F:

(S)-(−)-N-[[3-[3-Fluoro-4-(dihydrothien-3-yl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(5S)—N-[[3-[3-Fluoro-4-(2,5-dihydro-1-oxido-3-thienyl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(5S)—N-[[3-[3-Fluoro-4-(4,5-dihydro-1-oxido-3-thienyl)-phenyl-]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)—N-[[3-[3-Fluoro-4-(2,5-dihydro-1,1-dioxido-3-thienyl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)—N-[[3-[3-Fluoro-4-(4,5-dihydro-1,1-dioxido-3-thienyl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

A method for preparing compounds having a 6-membered heterocyclecontaining a nitrogen atom, sulfur atom, oxygen atom, sulfone group orsulfoxide group wherein R₃ and R₄ are hydrogen is depicted in CHART G.As shown in CHART G, the first step involves the condensation ofstructures 42 and 43 (wherein X is O, S or N) to afford compound 44. Inthe case where X is a nitrogen atom, the amino group should be protectedwith an appropriate protecting group such as carbobenzyloxy (CBz). Theprotecting group is optionally removed after the synthesis to givecompounds 46 or 47 (wherein X is NH), which can be used to prepare thederivative compounds demonstrated in CHART A. The reaction of 42 with 43occurs in an appropriate solvent such as THF, at an appropriatetemperature such as −78° C. to −40° C., in the presence of a lithiumbase such as n-butyllithium. The subsequent elimination reaction knownto those skilled in the art provides compound 45. The remainingsynthetic steps which lead to the compound 46 are similar to theprocedures outlined in CHART B. When it is desirable, the double bond inthe heterocyclic ring may be reduced to give 47 by catalytichydrogenation; and when X is a sulfur atom, the sulfur group can beoxidized to afford the corresponding sulfones and sulfoxides asdescribed above for CHART F.

CHART H depicts a method for preparing compounds having a 6-memberedheterocycle wherein substitutes R₃ and/or R₄ are halo. As shown in CHARTH, structure 48 (X is O, S, or NR wherein R is an appropriate protectinggroup) is reacted with a protected aniline 19 in the presence of anappropriate base, such as sec-butyllithium in an appropriate solventsuch as THF at a temperature in the range of −40° C. to −78° C.,followed by the addition of zinc chloride and an appropriate catalystsuch as tetrakis(triphenylphosphine) palladium with further reaction atreflux to afford compound 49. Optionally, in the case where X isnitrogen, structure 49 can be reduced to the saturated derivatives atthis point and carried on, or structure 49 can be acylated by thereaction known to those skilled in the art to provide structure 50. Theremaining synthetic steps which lead to compound 51 are similar to theprocedures outlined in CHART B. In the case where X is a sulfur atom,the sulfur group of structure 51 can be oxidized to afford thecorresponding sulfones and sulfoxides as described above. In addition,where X is O, NR, or SO₂, structure 51 may be reduced to saturatedderivatives by catalytic hydrogenation in the presence of an appropriatecatalyst and a suitable solvent to provide the saturated derivative 52.As stated above, in the case where X is a nitrogen atom, the amino groupis protected during the preparation with an appropriate protectinggroup. In this case, the preferred protecting group is 1,1-dimethylethylcarbamate (BOC). The protecting group is removed after the synthesis,and the resultant compound can use to prepare the derivative compoundsdemonstrated in CHART A.

The following compounds of Formula (I) having a 6-membered heterocyclecontaining a nitrogen atom, sulfur atom, oxygen atom, sulfone group orsulfoxide group, for example, are prepared directly by the methods ofCHART A, CHART G, and CHART H:

(S)-(−)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid phenylmethyl ester;

(S)-(−)-N-[[2-Oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-[(Benzyloxy)acetyl]-4-piperidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-4-piperidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-[(Benzyloxy)acetyl]-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-[(Benzyloxy)acetyl]-4-piperidinyl]-3,5-difluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-4-piperidinyl]-3,5-difluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Indole-2-carbonyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Isoxazole-5-carbonyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Methylsulfonyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid methyl ester;

(S)-(−)-N-[[3-[4-[1-(Cyanomethyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(2-Fluoroethyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Formyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-4-[4-[5-[[(2,2-Dichloroacetyl)amino]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester;

(S)-(−)-2,2-Dichloro-N-[[2-oxo-3-[3-fluoro-4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-2,2-Dichloro-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-2,2-Dichloro-N-[[2-oxo-3-[3-fluoro-4-[1-(hydroxyacetyl)-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[Tetrahydro-2H-pyran-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide;

(S)-(−)-N-[[3-[3-Fluoro-4-(tetrahydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-pyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[Tetrahydro-2H-pyran-4-yl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS-dioxide;

(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS-oxide;

(S)-(−)-N-[[3-[4-(Tetrahydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide;

(S)-(−)-N-[[3-[4-[1-(4-Oxo-2-thiazolinyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(5-Methyl-1,3,4-thiadiazol-2-yl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide.

CHART I depicts a method for preparing compounds of intermediate 1 whichhave a partially saturated 6-membered heterocycle containing nitrogen ishighly enantiomerically enriched form. As shown in CHART I, the firststep involves the coupling of structure 53 and structure 54 to providecompounds 55 and 56. The triflate group of structure 53 may be at eitherside of the double bond, wherein both are readily prepared from thecorresponding commercially available ketones. The structure 54 may beprepared according to the procedures described in PCT/US92/08267 andPCT/US93/09589. The reaction occurs over a few days, e.g. 1-5 days inthe presence of an appropriate catalyst such astris(dibenzylideneacetone)dipalladium(0). The amino protecting group of55 is removed by treatment with iodotimethylsilane and that of 56 isremoved by treatment with either trifluoroacetic acid oriodotrimethylsilane to give the corresponding compounds 57 and 58.Compounds 57 and 58 can be used to prepare the derivative compoundsdemonstrated in CHART A.

Following the general procedure as described above, and makingnon-critical variations by substituting 7- or 8-membered rings for the6-membered ring of structure 53, compounds that have a 7- or 8-memberedheterocycle containing nitrogen in highly enantiomerically enriched formcan be prepared. Their preparations are illustrated in further detail inEXAMPLEs 75 to 79.

The following compounds of Formula (I) for example, are prepareddirectly by the methods of CHART A and CHART I:

(S)-(−)-N-[[3-[4-[1-(4-Oxo-2-thiazolinyl)-3,6-dihydro-2H-pyridin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide.

(S)-(−)-N-[[3-[4-[1-(5-Methyl-1,3,4-thiadiazol-2-yl)-3,6-dihydro-2H-pyridin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide.

(S)-(−)-N-[[2-Oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-3,6-dihydro-2H-pyridin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Formyl)-3,6-dihydro-2H-pyridin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid methyl ester;

(S)-(−)-N-[[2-Oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[2-Oxo-3-[4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-3,6-dihydro-2H-pyridin-4-yl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Formyl)-3,6-dihydro-2H-pyridin-4-yl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid methyl ester;

(S)—N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-5,6-dihydro-2H-pyridin-3-yl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)—N-[[3-[4-[1-(Hydroxyacetyl)-5,6-dihydro-2H-pyridin-3-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)—N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,4,7-tetrahydro-1H-azepin-5-yl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-2,3,4,7-tetrahydro-1H-azepin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,6,7-tetrahydro-1H-azepin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide;

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-2,3,4,7-tetrahydro-1H-azepin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide;

(5S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)hexahydro-1H-azepin-4-yl]-3-fluorophenyl]2-oxo-5-oxazolidinyl]methyl]acetamide;

A second method for preparing compounds of intermediate 1 which have apartially saturated 6-membered heterocycle containing nitrogen in highlyenantiomerically enriched form is depicted in CHART J. As shown in CHARTJ, structure 59 is reacted with a protected aniline 19 to affordstructure 60. The subsequent acylation reaction provides structure 61which is treated with an appropriate acid to give a mixture of 62 and63. The regioisomers can be separated by chromatography as described inEXAMPLEs 72 and 73 and carried on. The protecting groups then areremoved by treatment with iodotrimethylsilane to give the desiredcompounds 64 and 57, which can be used to prepare the derivativecompounds demonstrated in CHART A. Use of the 4-keto isomer of structure59 provides an alternate route to the 4-isomer, structure 58.Alternatively, the hydroxy group of structure 61 or its 4-isomer may bereplaced by a fluoro atom using an appropriate agent such asdiethylaminosulfur trifluoride in an appropriate solvent such asmethylene chloride. The elimination step shown for structure 61 is notconducted in this situation. This replacement reaction is furtherdetailed in EXAMPLE 74.

The following compounds of Formula (I) for example, are prepareddirectly by the methods of CHART A and CHART J.

(S)—N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-3,4-dihydro-2H-pyridin-5-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-3,4-dihydro-2H-pyridin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

(S)-(−)-N-[[3-[4-[1-Formyl-4-fluoro-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide.

These compounds are useful for treatment of microbial infections inhumans and other warm blooded animals, under both parenteral and oraladministration.

The pharmaceutical compositions of this invention may be prepared bycombining the compounds of Formula (I) of this invention with a solid orliquid pharmaceutically acceptable carrier and, optionally, withpharmaceutically acceptable adjuvants and excipients employing standardand conventional techniques. Solid form compositions include powders,tablets, dispersible granules, capsules, cachets and suppositories. Asolid carrier can be at least one substance which may also function as adiluent, flavoring agent, solubilizer, lubricant, suspending agent,binder, tablet disintegrating agent, and encapsulating agent. Inertsolid carriers include magnesium carbonate, magnesium stearate, talc,sugar, lactose, pectin, dextrin, starch, gelatin, cellulosic materials,low melting wax, cocoa butter, and the like. Liquid form compositionsinclude solutions, suspensions and emulsions. For example, there may beprovided solutions of the compounds of this invention dissolved in waterand water-propylene glycol and water-polyethylene glycol systems,optionally containing suitable conventional coloring agents, flavoringagents, stabilizers and thickening agents.

Preferably, the pharmaceutical composition is provided employingconventional techniques in unit dosage form containing effective orappropriate amounts of the active component, that is, the compound ofFormula (I) according to this invention.

This quantity of active component, that is the compound of Formula (I)according to this invention, in the pharmaceutical composition and unitdosage form thereof may be varied or adjusted widely depending upon theparticular application, the potency of the particular compound, thedesired concentration. Generally, the quantity of active component willrange between 0.5% to 90% by weight of the composition.

In therapeutic use for treating, or combatting, bacterial infections inwarm-blooded animals, the compounds or pharmaceutical compositionsthereof will be administered orally and/or parenterally at a dosage toobtain and maintain a concentration, that is, an amount, or blood-levelof active component in the animal undergoing treatment which will beantibacterially effective. Generally, such antibacterially effectiveamount of dosage of active component will be in the range of about 0.1to about 100, more preferably about 3.0 to about 50 mg/kg of bodyweight/day. It is to be understood that the dosages may vary dependingupon the requirements of the patient, the severity of the bacterialinfection being treated, and the particular compound being used. Also,it is to be understood that the initial dosage administered may beincreased beyond the above upper level in order to rapidly achieve thedesired blood-level or the initial dosage may be smaller than theoptimum and the daily dosage may be progressively increased during thecourse of treatment depending on the particular situation. If desired,the daily dose may also be divided into multiple doses foradministration, e.g., 2-4 four times per day.

The compounds of Formula (I) according to this invention areadministered parenterally, i.e., by injection, for example, byintravenous injection or by other parenteral routes of administration.Pharmaceutical compositions for parenteral administration will generallycontain a pharmaceutically acceptable amount of the compound accordingto Formula (I) or a soluble salt (acid addition salt or base salt)dissolved in a pharmaceutically acceptable liquid carrier such as, forexample, water-for-injection and a buffer to provide a suitable bufferedisotonic solution, for example, having a pH of about 3.5-6. Suitablebuffering agents include, for example, trisodium orthophosphate, sodiumbicarbonate, sodium citrate, N-methylglucamine, L(+)-lysine andL(+)-arginine to name but a few representative buffering agents. Thecompound according to Formula (I) generally will be dissolved in thecarrier in an amount sufficient to provide a pharmaceutically acceptableinjectable. concentration in the range of about 1 mg/mL to about 400mg/mL of solution. The resulting liquid pharmaceutical composition willbe administered so as to obtain the above-mentioned antibacteriallyeffective amount of dosage. The compounds of Formula (I) according tothis invention are advantageously administered orally in solid andliquid dosage forms.

Antimicrobial activity was tested in vivo using the Murine Assayprocedure. Groups of female mice (six mice of 18-20 grams each) wereinjected intraperitoneally with bacteria which were thawed just prior touse and suspended in brain heart infusion with 4% brewers yeast(Staphylococcus aureus) or brain heart infusion (Streptococcus species).Antibiotic treatment at six dose levels per drug was administered onehour and five hours after infection by either oral intubation orsubcutaneous routes. Survival was observed daily for six days. ED₅₀values based on mortality ratios were calculated using probit analysis.The subject compounds are compared against well-known antimicrobialsvancomycin and U-100592 as controls. See “Upjohn OxazolidinoneAntibacterial Agent”, posters presented at the 35th InterscienceConference on Antimicrobial Agents and Chemotherapy. The data are shownin Table 1 and Table 2.

TABLE 1 EXAMPLE No. ED₅₀(mg/kg) Vancomycin ED₅₀(mg/kg) 3 5.00 3.004 >20.00 3.10 5 3.60 1.30 6 >20.00 5.00 10 20.00 2.00 11 >20.00 2.90 1220.00 2.00 13 >10.00 1.50 16 17.00 3.60 19 6.80 1.80 21 >20.00 1.80 222.30 2.40 23 >20.00 1.60 24 >20.00 1.90 28 15.30 1.90 29 5.00 1.90 3310.60 1.60 34 6.30 1.60 37 8.70 1.80 89 3.00 1.80 40 1.00 1.80 44 5.000.90 47 7.10 1.90

TABLE 2 EXAMPLE No. ED₅₀(mg/kg) U-100592 ED₅₀(mg/kg) 45 2.80 2.10 467.90 2.30 48 17.50 2.10 49 2.40 2.10 50 2.20 2.90 51 2.80 5.20 52 4.002.30 53 >20.00 2.30 54 6.60 2.90 55 2.30 2.50 56 4.40 2.70 57 6.20 2.7059 4.2 4.40 60 3.1 4.40 61 6.10 2.70 62 12.0 2.40 63 4.90 4.60 64 4.602.90 67 13.3 6.0 68(a) 3.50 3.50 69(a) 10.0 7.80 71 13.4 4.40 74 10.34.40 76 >20 3.50 78 6.0 3.20 83 7.50 4.10 84 6.50 4.10

In order to more fully illustrate the nature of the invention and themanner of practicing the same, the following experimental examples arepresented.

EXAMPLE 1(S)—N-[[3-[3-Fluoro-4-[1-(carbobenzyloxy)-(3-methyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1: Ethyl 1-cyano-1-(4-nitro-2-fluorophenyl)propionate

A flame-dried 3-neck 1-L round bottom flask equipped with a magneticspinbar and addition funnel was charged with 6.40 g sodium hydride(0.160 mol, 60% oil dispersion) followed by washing with pentane (3×40mL) and drying under house vacuum. The hydride was suspended in 100tetrahydrofuran, cooled to 0° C., and treated with a solution of ethylcyanacetate (8.6 mL, 0.080 mol) in 150 mL THF over 15 minutes with gasevolution. The resulting milky solution of enolate was stirred fiveminutes then treated with a solution of 3,4-difluoronitrobenzene (I)(8.8 mL, 0.080 mol) in 150 mL THF with immediate orange coloration. Thecooling bath was removed and the reaction mixture was warmed to 50° C.for 18 hours. The now red suspension was cooled to room temperature andsuccessively treated with 100 g iodomethane (0.72 mol), 33 g potassiumcarbonate (0.24 mol), and 100 mL acetone. The visually unchangedsolution was warmed to 60° C. for an additional 16 hours. The now tansuspension was cooled to room temperature, filtered through a pad ofCELITE, and the filtrate was concentrated in vacuo. The resultingresidue was diluted with 500 mL water and extracted twice with ethylacetate (500 mL). The combined organics were washed once with brine (300mL), dried over MgSo₄, filtered, and concentrated to give 21.39 g of abrown oil. This crude material was purified by LC on 850 g (230-400)silica gel eluting with 20% ethyl acetate/hexanes to afford 18.14 g(100%) of the title compound as a yellow oil that spontaneouslycrystallized. mp 56.0-57.0° C.; R_(f) 0.34 (20% ethyl acetate/hexanes);IR (neat) 1752, 1534, 1423, 1355, 1248, 1239, 1213, 1099, 811, 741 cm⁻¹;¹H NMR (300 MHz, CDCl₃) δ 8.16 (m, 1H, aromatic), 8.03 (dd, 1H, J=2.3Hz, J=10.4 Hz, aromatic), 7.80 (dd, 1H, J=7.6 Hz, J=8.6 Hz, aromatic),4.33 (m, 2H, O—CH₂), 2.04 (s, 3H, CH₃), 1.28 (t, 3H, J=7.2 Hz, O—CH₂—CH₃). HRMS Calcd for C₁₂H₁₁N₂O₄F₁+H₁: 267.0781. Found: 267.0799.

Step 2: Ethyl 1-aminomethyl-1-(4-amino-2-fluorophenyl)propionate

A solution of ethyl 1-cyano-1-(4-nitro-2-fluorophenyl)propionate (17.9g, 67.3 mmol) in absolute ethanol (500 mL) was treated with Raney-Nickel(30.9 g of a 50% slurry in water) and subjected to hydrogenation in aParr apparatus for 17 hours (25-30 psi H₂, room temperature). Thereaction mixture was then filtered through Celite (repeated EtOHwashings) and concentrated in vacuo (heat gun, Hi-vac) to give the titlecompound as a golden syrup (15.6 g, 97%). This material could bepurified by chromatography on silica gel using 15% methanol/ethylacetate but was typically carried on to the next step without furtherpurification: R_(f) 0.32 (15% MeOH/EtOAc); ¹H NMR (CDCl₃) δ 7.00 (t,J=8.5, 1H, aromatic), 6.45 (dd, J=8.2, 2.3, 1H, aromatic), 6.36 (dd,J=13.1, 2.4, aromatic), 4.18 (q, J=7.0, 3H, —CH₂ CH ₃), 3.76 (br s, 2H,NH₂), 3.06 (dd, J=18.2, 13.8, 2H, CH₂N), 1.52 (s, 3H, CCH₃), 1.21 (t,J=7.1, 2H, —CH ₂CH₃); IR (liquid) 1722, 1634, 1513, 1445, 1305, 1283,1243, 1172, 1132, 845 cm⁻¹; HRMS: Calcd (C₁₂H₁₇F₁N₂O₂) 240.1274; Found240.1293.

Step 3: 3-Methyl-3-(4-amino-2-fluorophenyl)-azetidinone

A solution of ethyl 1-aminomethyl-1-(4-amino-2-fluorophenyl)propionate(2.1 g, 8.7 mmol) in THF (50 mL) was added slowly via syringe to a cold(0° C.) solution of methyl magnesium bromide (15 mL of a 3 M solution inether, 45 mmol, diluted with 100 mL THF). When addition was complete,the syringe was rinsed with additional THF (2×12 mL). The cooling bathwas removed and the beige solution was allowed to stir at roomtemperature for three hours, at which point it was poured into saturatedammonium chloride (aq, ca. 500 mL) and volatiles were removed in vacuo.The resulting aqueous phase was extracted three times with t-butylmethyl ether and the combined organics were washed once with water, oncewith brine, dried over MgSO₄, filtered, and concentrated to give 1.4 gof a yellow syrup. Extraction of the aqueous phase with ethyl acetateprovided and additional 190 mg crude product. The crude products thusobtained were combined and chromatographed on silica gel using 50% ethylacetate/hexane to give the title compound (1.0 g, 60%) as a pale yellowsolid, mp 125-127° C.: R_(f) 0.21 (50% EtOAc/hexane); ¹H NMR (CDCL₃)δ7.46 (t, J=8.3, 1H, aromatic); 6.43-6.35 (m, 2H, aromatics), 5.77 (br s,1H, NH), 3.75 (br,s, 2H, NH₂), 3.54 (dd, J=5.5, 2.4, 1H, CH₂), 3.45 (d,J=5.5, 1H, CH₂), 1.64 (s,3H, CH₃); IR (mull) 3439, 3342, 3236, 1738,1635, 1516, 1441, 1210, 1146, 631 cm⁻¹; Anal. calcd for C₁₀H₁₁F₁N₂O₂; C,61.84, H, 5.71, N, 4.43. Found: C, 62.13, H 5.81, N, 14.36.

Step 4: 3-(4-Amino-2-fluorophenyl)-3-methylazetidine

A flame-dried 3-neck 2-L round bottom flask equipped with mechanicalstirrer, reflux condenser, and addition funnel was charged with 300 mLtetrahydrofuran and 350 mL 1M lithium aluminumhydride (0.35 mol)followed by cooling to 0° C. This solution was treated with a solutionof 9.85 g 3-Methyl-3-(4-amino-2-fluorophenyl)-2-azetidinone (0.051 mol)in 210 mL THF with gas evolution and a yellow coloration. The coolingbath was removed and the reaction was heated to reflux with the rapidformation of a white precipitate. After 20 hours, the visually unchangedreaction mixture was cooled to room temperature and quenched by thesuccessive addition of 13 mL water, 12 mL 5M sodium hydroxide, and 47 mLwater. The resulting thick gelatinous suspension was diluted with one Lethyl acetate, filtered through a pad of CELITE, concentrated, and highvacuum dried to afford 9.82 g of the title compound as a light orangesyrup. ¹H NMR (300 MHz, CDCl₃) δ 6.78 (t, 1H, J=8.5 Hz, aromatic), 6.37(m, 2H, aromatic), 4.06 (d, 2H, J=8.2 Hz, N—CH_(2a)s), 3.81 (bs, 3H,NHs), 3.58 (d, 2H, J=8.2 Hz, N—CH_(2b)s), 1.65 (s,3H, CH₃).

Step 5:N-Carbobenzyloxy-3-(N-carbobenzyloxy-3-flouroanilin-4-yl)3-methylazetidine

A 500 mL round bottom flask equipped with a magnetic spinbar andaddition funnel was charged with 85 mL water, 3.84 g sodium bicarbonate(0.46 mol) and a solution of 9.82 g3-(4-amino-2-fluorophenyl)-3-methylazetidine (0.051 mol theory) in 165mL acetone. The resulting orange suspension was cooled to 0° C. andtreated with 43 mL bensylchloroformate (0.30 mol) with gas evolution andthe reaction turning a light yellow color. The cooling bath was removedand the reaction mixture was stirred at room temperature for 65 hours.TLC indicates incomplete consumption of the starting aminoaniline and anadditional 12.8 g sodium bicarbonate (0.15 mol) and 14 mLbensylchloroformate (0.10 mol) was added with additional gas evolution.After two hours, the reaction mixture was diluted with 350 mL saturatedsodium bicarbonate and extracted three times with ethyl acetate (300mL). The combined organics were washed once with water (200 mL), oncewith brine (200 mL), dried over MgSO₄, filtered, and concentrated togive 29.86 g of a light yellow oil. This crude material was purified byLC on 850 g (230-400) silica gel eluting with 25% ethyl acetate/hexanesto afford 11.67 g (51%) of the title compound as a light yellow solid.R_(f) 0.18 (25% ethyl acetate/hexanes); IR (neat) 1735, 1707, 1693,1600, 1534, 1455, 1424, 1414, 1221, 1081 cm⁻¹; ¹H NMR (300 MHz, CDCl³) δ7.35 (m, 11H, aromatic), 6.96 (m, 3H, aromatic & NH), 5.19 (s, 2H,Ph—CH₂), 5.09 (s, 2H, Ph—CH₂), 4.30 (d, 2H, J=8.2 Hz, N—CH_(2a)s), 4.00(d, 2H, J=8.4 Hz, N—CH_(2b)), 159 (s, 3 H, CH₃); ¹³C NMR (75 MHz, CDCl₃)160.4 (d, J_(CF)=245 Hz), 156.6, 153.0, 138.1 (d, J_(CF)=11 Hz), 136.5,135.7 128.6, 128.4, 128.2 127.9, 127.8, 127.5, 127.0, 126.9, 113.9,106.6 (d, J_(CF)=27 Hz), 67.1, 66.6, 60.8, 60.2, 36.1, 28.2; Anal. Calcdfor C₂₆H₂₅N₂O₄F₁: C, 69.63; H, 5.62; N, 6.25. Found: C, 69.37; H 5.69;N, 5.87.

Step 6:(R)-(-)-N-Carbobenzyloxy-3-methyl-3-[2-fluoro-4-[5-hydroxymethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine

A 500 mL round bottom flask containing 11.48 gN-carbobenzyloxy-3-(N-carbobenzyloxy-3-fluoroanilin-4-yl-3-methylazetidine(2.56 mmol) was equipped with a magnetic spinbar, charged with 100 mLtetrahydrofuran (freshly distilled), and cooled to −78° C. This lightyellow homogenous solution was treated with 16.6 mL n-butyllithium (26.6mmol) with a slight darkening in color. The carbamate ion was stirred 30minutes at this reduced temperature followed by treatment with 3.8 mLR-glycidylbutyrate (26.6 mmol) with no observable change. The coolingbath was removed and the reaction was warmed to room temperature for 16hours. The now orange opaque solution was diluted with 200 mL saturatedammonium chloride and extracted twice with ethyl acetate (250 mL). Thecombined organics were washed once with saturated sodium bicarbonate(200 mL), once with brine (300 mL), dried over MgSO₄, filtered, andconcentrated to give 15.72 g of the title compound as an orange oil.This crude material was purified by LC on 530 g (230-400) silica geleluting with 80% ethyl acetate/hexanes to afford 6.79 g (64%) of a lightyellow amorphous solid. R_(f) 0.28 (80% ethyl acetate/hexane); [α]_(D)−35°(c 0.8967, methanol); IR (neat) 1754, 1708, 1516, 1454, 1429, 1415,1358, 1228, 1194, 1076 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.44 (dd, 1H,J=2.2 Hz, J=13.0 Hz, aromatic), 7.33 (m, 5H, aromatic), 7.19 (dd, 1H,J=2.2 Hz, J=8.5 Hz, aromatic), 7.03 (t, 1H, J=8.7 Hz, aromatic), 5.09(s, 2H, Ph—CH₂), 4.73 (m, 1H, methine), 4.30 (d, 2H, J=8.2 Hz,Ph—C—CH_(2a)s), 3.97 (m, 5H, Ph—C—CH_(2b)s, Ph—N—CH₂s, HO—CH_(2a)), 3.73(m, 1H, HO—CH _(2b)), 2.80 (t, 1H, J=6.3 Hz, HO), 1.60 (s, 3H, CH₃); ¹³CNMR (75 MHz, CDCl₃) 160.2 (d, J_(CF)=246 Hz), 156.5, 154.2, 138.0 (d,J_(CF)=11 Hz), 136.3, 128.2, 128.1, 127.8, 127.7, 126.9 (d, J_(CF)=7Hz), 113.1 (d, J_(CF)=3Hz), 106.2 (J_(CF)=27 Hz), 72.6, 66.5, 62.4,60.1, 46.0, 35.9, 28.0; Melt solvate=3.8% ethyl acetate; Anal. Calcd forC₂₂H₂₃N₂O₅F₁ plus 3.8% ethyl acetate: C,63.41; H, 5.73; N, 6.50. Found:c, 63.15; H, 5.52 ; N, 6.58. HRMS Calcd for C₂₂H₂₃N₂O₅F₁: 415.1169.Found: 415.1674.

Step 7:(R)-(-)-N-Carbobenzyloxy-3-methyl-3-[2-fluoro-4-[5-hydroxymethyl-2-oxo-3-oxazolidinyl]phenyl]azetidinemethone sulfuride ester

A 500 mL round bottom flask containing 6.55 g(R)-(-)-N-carbobenzyloxy-3-methyl-3-[2-fluoro-4-[5-hydroxymethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine(15.3 mmol) was equipped with a magnetic spinbar, charged with 150 mLdichloromethane, and cooled to 0° C. This light yellow homogenoussolution was treated successively with 3.2 mL triethylamine (23.0 mmol)and 1.4 mL methanesulfonyl chloride (18.4 mmol) with no observablechange. The cooling bath was removed and the reaction mixture was warmedto room temperature for one hour. The visually unchanged solution wasdiluted with 100 mL 0.5 N hydrochloric acid, shaken, layers separatedand the acidic layer extracted once with dichloromethane (100 mL). Thecombined organics were washed once with brine (75 mL), dried over MgSO₄,filtered, and concentrated to give 7.68 g (100%) of the title compoundas a light yellow amorphous solid, R_(f) 0.40 (80% ethylacetate/hexane); IR (mull) 1758, 1703, 1516, 1418, 1358, 1337, 1230,1176, 1075, 965 cm⁻¹; ¹HNMR (300 MHz, CDCl₃) δ 7.44 (dd, 1H, J=2.2 Hz,J=12.8 Hz, aromatic), 7.33 (m, 5H, aromatic), 7.17 (dd, 1H, J=2.2 Hz,J=8.5 Hz, aromatic), 7.06 (t, 1H, J=8.5 Hz, aromatic), 5.10 (s, 2H,Ph—CH₂), 4.92 (m, 1H, methine), 4.50 (dd, 1H, J=3.6 Hz, J=11.7 Hz,MsO—CH_(2a)), 4.42 (dd, 1H, J=4.1 Hz, J=11.7 Hz, MsO—CH_(2b)) 4.31 (d,2H, J=8.1 Hz, Ph—C—CH_(2a)s), 4.13 (t, 1H, J=9.2 Hz, Ph—N—CH_(2a)), 4.0(d, 1H, J=8.5 Hz, Ph—C—CH_(2b)s); 3.94 (dd, 1H, J=6.2 Hz, J=9.2 Hz,Ph—N—CH_(2b)), 3.10 (s, 3H, S—CH₃), 1.62 (s, 3H, C—CH₃); ¹³C NMR (75MHz, CDCl₃) 160.3 (d, J_(CF)=247 Hz), 156,6, 153.3, 137.6 (d, J_(CF)=11Hz), 136.4, 129.0, 128.8, 128.3, 127.9, 127.8, 127.3, 127.2 (d, J_(CF)=6Hz), 113.3 (d, J_(CF)=3 Hz),106.5 (d, J_(CF)=28 Hz), 69.4, 67.8, 66.6,60.4, 46.2, 37.7, 36.1, 28.1; Anal. Calcd for C₂₃H₅N₂O₇F₁S₁: C, 56.09;H, 5.12; N, 5.69. Found: C, 55,76; H, 517; N, 5.61.

Step 8:(R)-(-)-N-Carbobenzyloxy-3-methyl-3-[2-fluoro-4-[5-aminomethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine

Two oven-dried 100 mL sealable tubes equipped with magnetic spinbarswere equally charged with a solution of 7.50 g(R)-(-)-N-carbobenzyloxy-3-methyl-3-[2-fluoro-4-[5-hydroxymethyl-2-oxo-3-oxazolidinyl]phenyl]azetidinemethone sulfuride ester (15.2 mmol) in 75 mL methanol and 75 mLtetrahydrofuran (freshly distilled). These light yellow homogenoussolutions were saturated with gaseous ammonia over ten minutes becomingalmost colorless, sealed with teflon screwcaps, and heated to 100° C.for 64 hours. The reaction mixtures were combined and concentrated toafford the title compound as a crude yellow foam.

Step 9:(S)-N-[[3-[3-Fluoro-4-[1-(carbobenzyloxy)-(3-methyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

The title compound was prepared as follows:(R)-(-)-N-carbobenzyloxy-3-methyl-3-[2-fluoro-4-[5-aminomethyl-2-oxo-3-oxazolidinyl]phenyl]azetidinewas diluted with 220 mL dichloromethane, cooled to 0° C., andsuccessively treated with 3.7 mL pyridine (46 mmol) and 1.8 mL aceticanhydride (19 mmol) with no observable change. The cooling bath wasremoved and the reaction mixture was warmed to room temperature for 16hours. The visually unchanged solution was concentrated to a yellowfoam, rediluted with 50 mL dichloromethane, and filtered to remove theremaining insoluble precipitate. The filtrate was purified by LC on 340g (230-400) silica gel eluting with 2.5% methanol/ethyl acetate toafford 5.85 g (84%) of(S)-N-[[3-[3-fluoro-4-[1-(carbobenzyloxy)-(3-methyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamideas a colorless glass. R_(f) 0.24 (2.5% methanol/ethyl acetate); [α]_(D)−19°(c 0.9971, methanol); IR (mull) 1754, 1706, 1676, 1516, 1430, 1415,1357, 1227, 1194, 1075, cm⁻¹, ¹H NMR (300 MHz, CDCl₃) δ 7.42 (dd, 1H,J=2.1 Hz, J=12.9 Hz, aromatic), 7.33 (m, 5H, aromatic), 7.13 (dd, 1H,J=2.2 Hz, J=8.5 Hz, aromatic), 7.04 (t, 1H, J=8.5 Hz, aromatic), 6.56(bt, 1H, J=6.2 Hz, NH), 5.10 (s, 2H, Ph—CH₂), 4.79 (m, 1H, methine),4.30 (d, 2H, J=8.2 Hz, Ph—C—CH_(2a)s), 4.01 (m, 3H, Ph—C—CH_(2b)s,Ph—N—CH_(2a)), 3.78 (dd, 1H, J=6.7 Hz, J=9.1 Hz, Ph—N—CH_(2b)),3.64 (m,2H, NH—CH ₂s), 2.02 (s, 3H, O═C—CH₃), 1.60 (s, 3H, Ph—C—CH₃); ¹³C NMR(75 MHz, CDCl₃) 171.2, 160.3 (d, J_(CF)=246 Hz), 156.6, 154.2, 137.9 (d,J_(CF)=11 Hz), 136.5, 128.9 (d, J_(CF)=14 Hz), 128.4, 127.9, 127.2 (d,J_(CF)=7 Hz) 113.2 (d, J_(CF)=2 Hz), 106.4 (d, J_(CF)=28 Hz), 72.0,66.6, 60.7, 60.3, 47.3, 41.7, 36.1, 28.1, 22.9; Anal. Calcd forC₂₄H₂₆N₃O₅F₁: C, 63.29; H, 5.75; N, 9.23. Found: C,62.98; H, 5.96; N,8.98.

EXAMPLE 2(S)-N-[[3-[3-Fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

A 500 mL Parr flask was charged with a solution of 5.83 g(S)-N-[[3-[3-fluoro-4-[1-(carbobenzyloxy)-(3-methyl)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(12.8 mmol) in 100 mL methanol and 1.17 g 10% palladium on carbon. Theblack suspension was placed under 40 psi hydrogen with shaking for fourhours with the pressure remaining constant at 28 psi. The Parr wasremoved from the hydrogenator, the reaction mixture was filtered througha pad of CELITE, and concentrated to afford 4.05 g (99%) of an off-whiteamorphous solid. A 1.00 g portion of this material was purified by LC on100 g (230-400) silica gel eluting with 2:17:83NH₄OH/methanol/dichloromethane to afford 776 mg of the title compound asa colorless glass. R_(f) 0.26 (2:17:83 NH₄OH/methanol/dichloromethane);[α]_(D) −23°(c 0.9015, methanol); IR (mull) 1752, 1662, 1630, 1554,1515, 1483, 1435, 1412, 1227, 1194, cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.37(dd, 1H, J=2.2 Hz, J=12.8 Hz, aromatic), 7.12 (dd, 1H, J=2.2 Hz, J=8.5Hz, aromatic), 6.99 (t, 1H, J=8.6 Hz, aromatic), 6.33 (bt, 1H, J=6 Hz,O═C—NH), 4.78 (m, 1H, methine), 4.40 (m, 3H, Ph—C—CH_(2a)s),Ph—N—CH_(2a)), 3.78 (dd, J=6.8 Hz, J=9.1 Hz, Ph—N—CH_(2b)), 3.66 (m, 2H,NH—CH ₂s), 3.56 (d, 2H, J=7.8 Hz, Ph—C—CH_(2b)s) 2.40 (bs, 1H, NH), 2.02(s, 3H, O═C—CH₃), 1.67 (s, 3H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.2,160.0 (d, J_(CF)=246 Hz), 154.2, 137.3 (d, J_(CF)=11 Hz), 130.8 (d,J_(CF)=15 Hz), 126.9 (d, J_(CF)=7 Hz) 113.2, 106.3 (d, J_(CF)=27 Hz),71.9, 58.0, 47.3, 41.7, 40.5, 27.3, 22.9; K.F. Water=0.89%; Anal. Calcdfor C₁₆H₂₀N₃O₃F₁ with 0.89% water: C, 59.27; H, 6.32; N, 12.96. Found:c, 5907;H, 6.45; N, 12.89. HRMS Calcd for C₁₆H₂₀N₃O₃+H₁: 322.1567.Found: 322.1569.

EXAMPLE 3(S)-N-[[3-[3-Fluoro-4-[1-(carboxymethyl)-3-(3-methyl)-azetidinyl]-phenyl]2-oxo-5-oxazolidinyl]methyl]-acetamide

A oven-dried 25 mL round bottom flask equipped with magnetic spinbar wascharged with 241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 8 mL dichloromethane, and cooled to 0° C. The colorless butslightly opaque solution was treated with 0.16 mL triethylamine (1.1mmol) and 70 μL methylchloroformate (0.90 mmol) with the reactionmixture becoming clear. The cooling bath was removed and the reactionmixture was warmed to room temperature over two hours. The visuallyunchanged solution was diluted with 30 mL dichloromethane, washed oncewith water (20 mL), once with brine (15 mL), dried over MgSO₄, filtered,and concentrated to give 267 mg of a white foam. This crude material waspurified by LC on 18 g (230-400) silica gel eluting with 5%methanol/dichloromethane to afford 219 mg (77%) of the title compound asa white foam. R_(f) 0.30 (5% methanol/dichloromethane); [α]_(D) −21°(c1.0194, methanol); IR (mull) 1755, 1706, 1676, 1631, 1517, 1394, 1227,1208, 1195, 1076, cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.43 (dd, 1H, J=2.2Hz, J=12.9 Hz, aromatic), 7.14 (dd, 1H, J=2.2 Hz, J=8.5 Hz, aromatic),7.05 (t, 1H, J=8.6 Hz, aromatic), 6.35 (bt, 1H, J=6 Hz, NH), 4.80 (m,1H, methine), 4.28 (d, 2H, J=8.2 Hz, CO₂—N—CH_(2a)s), 4.04 (t, 1H, J=9.0Hz, Ph—N—CH_(2a)), 3.97 (d, 2H, J=8.4 Hz, CO₂—N—CH_(2b)s), 3.77 (dd, 1H,J=6.7 Hz, J=9.1 Hz, Ph—N—CH_(2b)), 3.68 (m, 5H, NH—CH₂s, OCH₃), 2.03 (s,3H, O═C—CH₃), 1.161 (s, 3Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 170.9, 160.2(d, J_(CF)=246 Hz), 157.1, 154.0, 137.8 (d, J_(CF)=11 Hz), 128.5 (d,J_(CF)=15 Hz), 127.0 (d, J_(CF)=7 Hz) 113.1, (d, J_(CF)=3 Hz), 106.3 (d,J_(CF=)27 Hz), 7.18, 60.4, 52.1, 47.2, 41.7, 35.9, 28.0, 22.9; K.F.Water=1.19%; Anal. Calcd for C₁₈H₂₂N₃O₅F₁ with 1.19% water: C, 56.31; H,5.91; N, 10.94. Found: c, 56.27; H, 5.93; N, 10.93.

EXAMPLE 4(S)-N-[[3-[3-Fluoro-4-[1-(methoxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]2-oxo-5-oxazolidinyl]methyl]-acetamide

A oven-dried 25 mL round bottom flask equipped with magnetic spinbar wascharged with 241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 8 mL dichloromethane, and cooled to 0° C. The colorless butslightly opaque solution was treated with 0.16 mL triethylamine (1.1mmol) and 85 μL methoxyacetychloride (0.90 mmol) with a smokey/hazedeveloping. The cooling bath was removed and the reaction mixture waswarmed to room temperature over two hours. The now clear colorlesssolution was diluted with 25 mL dichloromethane, washed once with water(15 mL), once with brine (15 mL), dried over MgSO ₄, filtered, andconcentrated to give 294 mg of a white foam. This crude material waspurified by LC on 27 g (230-400) silica gel eluting with 7%methanol/dichloromethane to afford 240 mg (81%) the tile compound as awhite amorphous solid. R_(f) 0.23 (7% methanol/dichloromethane); [α]_(D)−20°(c 0.9736, methanol); IR (mull) 1754, 1662, 1654, 1632, 1517, 1437,1412, 1226, 1194, 1122, cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.45 (dd, 1H,J=2.1 Hz, J=13.0 Hz, aromatic), 7.15 (dd, 1H, J=2.1 Hz, J=8.5 Hz,aromatic), 7.07 (t, 1H, J=8.5 Hz, aromatic), 6.47 (bt, 1H, J=6 Hz, NH),4.80 (m, 1H, methine), 4.51 (d, 1H, J=9.0 Hz, Ph—C—CH_(2a)), 4.35 (d,1H, J=9.7 Hz, Ph—C—CH_(2b)), 4.25 (d, 1H, J=9.2 Hz, Ph—C—CH_(2a)), 4.05(m, 4H, O═C—CH₂s, Ph—C—CH_(2b), Ph—N—CH_(2a)), 3.66 (m, 1H,PH—N—CH_(2b)), 3.66 (m, 2H, NH—CH₂s, 2.03 (s, 3H, O═C—CH₃) 1.63 (s, 3H,Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.2, 169.7, 160.4 (d, J_(CF)=246Hz), 154.2, 138.2, (d, J_(CF)=11 Hz), 128.4 (d, J_(CF)=14 Hz), 127.3 (d,J_(CF)=6 Hz) 113.4, 106.6 (d, J_(CF)=28 Hz), 72.1, 71.5, 62.4, 59.5,59.2, 47.5, 41.9, 36.9, 28.3, 23.1; K.F. Water=2.03%; Anal. Calcd forC₁₉H₂₄N₃O₅F₁ plus with 2.03% water: C, 56.83; H, 6.25; N, 10.47. Found:C, 56.99; H, 6.34; N, 10.49. HRMS Calcd for C₁₉H₂₄N₃O₅F₁: 394.1778.Found: 394.1784.

EXAMPLE 5(S)-N-[[3-[3-Fluoro-4-[1-(formyl)-3-(3-methyl)-azetidinyl]-phenyl]2-oxo-5-oxazolidinyl]methyl]-acetamide

A oven-dried 25 mL round bottom flask equipped with magnetic spinbar wascharged with 241 mg(S)-N-[[3-[3-Fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 8 mL dichloromethane, and cooled to 0° C. The colorless butslightly opaque solution was treated with 0.16 mL triethylamine (1.1mmol) and 73 μL ethyl formate (0.90 mmol) with no observable change. Thecooling bath was removed and the reaction mixture was warmed to roomtemperature for 16 hours. TLC analysis of the now clear solutionindicated incomplete consumption of(S)-N-[[3-[3-Fluoro-4-[3-methyl-3-axetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide.The reaction mixture was treated with an additional 0.14 mL ethylformate (1.8 mmol) and 8.0 mL 1N sodium hydroxide with vigorous stirringfor five minutes. The reaction was diluted with 10 mL water andextracted twice with dichloromethane (25 mL). The combined organics werewashed once with water (20 mL), once with brine (20 mL), dried overMgSO₄, filtered, and concentrated to give 253 mg of a white foam. Thiscrude material was purified by LC on 18 g (230-400) silica gel elutingwith 6% methanol/dichloromethane to afford 145 mg (55%) the titlecompound as a white amorphous solid. R_(f) 0.25 (7%methanol/dichloromethane); [α]_(D) −20°(c 0.9949, methanol); IR (mull)1754, 1666, 1631, 1548, 1516, 1478, 1433, 1414, 1227, 1195, cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 8.06 (s, 1H, CHO), 7.47 (dd, 1H, J=2.0 Hz, J=13.0 Hz,aromatic), 7.16 (dd, 1H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.07 (t, 1H,J=8.6 Hz, aromatic), 6.33 (bt, 1H, J=6 Hz, NH), 4.80 (m, 1H, methine),4.42 (d, 1H, J=8.2 Hz, Ph—C—CH_(2a)), 4.30 (d, 1H, J=9.9 Hz,Ph—C—CH_(2b)), 4.15 (d, 1H, J=8.3 Hz, Ph—C—CH_(2a)), 4.05 (m, 2H,Ph—C—CH_(2b), Ph—N—CH_(2a)), 3.79 (dd, 1H, J=6.8 Hz, J=9.1 Hz,PH—N—CH_(2b)), 3.67 (m, 2H, NH—CH₂s), 2.03 (s, 3H, O═C—CH₃), 1.64 (s,3H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.1, 162.3, 160.3 (d,J_(CF)=246 Hz), 154.1, 138.2, (d, J_(CF)=11 Hz), 127.9 (d, J_(CF)=14Hz), 127.1 (d, J_(CF)=6 Hz), 113.3, 106.4 (d, J_(CF)=27 Hz), 71.9, 59.6,58.2, 47.3, 41.7, 37.6, 28.0, 23.0; HRMS Calcd C₁₇H₂₀N₃O₄F₁: 349.1438.Found: 349.1444.

EXAMPLE 6(S)-N-[[3-[3-Fluoro-4-[1-(dichloroacetyl)-3-(3-methyl)-azetidinyl]-phenyl]2-oxo-5-oxazolidinyl]methyl]-acetamide

A oven-dried 25 mL round bottom flask equipped with magnetic spinbar wascharged with 241 mg(S)-N-[[3-[3-Fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 8 mL dichloromethane, and cooled to 0° C. The colorless butslightly opaque solution was treated with 0.16 mL triethylamine (1.1mmol) and 87 μL dichloroacetyl chloride (0.90 mmol) with a smokey/hazedeveloping. The cooling bath was removed and the reaction mixture waswarmed to room temperature over three hours. The now clear colorlesssolution was diluted with 15 mL water and extracted twice withdichloromethane (25 mL). The combined organics were washed once withbrine (15 mL), dried over MgSO₄, filtered, and concentrated to give 353mg of a tan foam. This crude material was purified by LC on 25 g(230-400) silica gel eluting with 5% methanol/dichloromethane to afford243 mg (75%) the title compound as an off-white amorphous solid. R_(f)0.26 (5% methanol/dichloromethane); [α]_(D) −18°(c 0.9862, methanol); IR(mull) 1752, 1666, 1631, 1545, 1517, 1440, 1412, 1288, 1227, 1193, cm⁻¹;¹H NMR (300 MHz, CDCl₃) δ 7.48 (dd, 1H, J=2.1 Hz, J=13.0 Hz, aromatic),7.18 (dd, 1H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.08 (t, 1H, J=8.6 Hz,aromatic), 6.52 (bt, 1H, J=6.1 Hz, NH), 4.81 (m, 1H, methine), 4.70 (d,1H, J=8.9 Hz, Ph—C—CH_(2a)), 4.48 (d, 1H, J=9.1 Hz, Ph—C—CH_(2b)), 4.41(d, 1H, J=10.1 Hz, Ph—C—CH_(2a)), 4.13 (d, 1H, J=10.0 Hz, Ph—C—CH_(2b)),4.06 (t, 1H, J=9.0 Hz, PH—N—CH_(2a)), 3.79 (dd, 1H, J 6.7Hz,Ph—N—CH_(2b)), 3.67 (m, 2H, NH—CH ₂s), 2.03 (s, 3 H, O═C—CH₃), 1.67 (s,3H, Ph—c—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.3, 163.1, 160.3 (d,J_(CF)=246 Hz), 154.2, 138.4, (d, J_(CF)=11 Hz), 127.6 (d, J_(CF)=15Hz), 127.1 (d, J_(CF)=6 Hz), 113.4, 106.6 (d, J_(CF)=27 Hz), 72.1, 64.6,63.1, 60.3, 47.4, 41.8, 36.9, 28.2, 23.0; K.F. Water=1.3%; Anal. Calcdfor C₁₈H₂₀N₃O₄F₁Cl₂ plus 1.3% water: C, 49.36; H, 4.75; N, 9.60. Found:C, 48.97; N, 9.53. HRMS Calcd for C₁₈H₂₀N₃O₄F₁Cl₂: 432.0893. Found:432.0900.

EXAMPLE 7(S)-N-[[3-[3-Fluoro-4-[1-(3-methoxypropionyl)-3-(3-methyl)-azetidinyl]-phenyl]2-oxo-5-oxazolidinyl]methyl]-acetamide

A oven-dried 10 mL round bottom flask equipped with magnetic spinbar wascharged with 241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 4 mL dichloromethane, 81 μL 3-methoxypropionic acid (0.83mmol), 0.13 mL of distilled diethylcyanophosphonate (0.83 mmol) andcooled to 0° C. The colorless solution was treated with 0.11 mLtriethylamine (0.78 mmol) becoming a pinkish color. The cooling bath wasremoved and the reaction mixture was warmed to room temperature over 66hours. The now reddish brown solution was diluted with 20 mLdichloromethane and washed once with water (15 mL), once with brine (15mL), dried over MgSO₄, filtered, and concentrated to give 297 mg of ared foam. This crude material was purified by LC on 18 g (230-400)silica gel eluting with 7% methanol/dichloromethane to afford 216 mg ofan off-white amorphous solid. ¹H NMR indicates this material to becontaminated with 10%(S)-N-[[3-[3-fluoro-4-[1-(formyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidiniyl]methyl]-acetamidewhich was removed by catalytic hydrogenolysis with 22 mg 10% palladiumon carbon in 30 mL tetrahydrofuran containing 10 drops concentratedhydrochloric acid. The resulting crude material was rechromatographed on13 g (230-400) silica gel eluting the 7% methanol/dichloromethane) toafford 135 mg (44% overall) the title compound as an off-white amorphoussolid. R_(f)0.23 (7% methanol/dichloromethane); [α]_(D) −19°(c 0.8324,methanol); IR (mull) 1755, 1644, 1630, 1548, 1516, 1440, 1410, 1226,1192, 1115, cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.45 (dd, 1H, J=2.0 Hz,J=12.9 Hz, aromatic), 7.15 (dd, 1H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.07(t, 1H, J=8.5 Hz, aromatic), 6.29 (bt, 1H, J=6 Hz, NH), 4.80 (m, 1H,methine), 4.42 (d, 1H, J=8.0 Hz, Ph—C—CH_(2a)), 4.30 (d, 1H, J=9.6 Hz,Ph—C—CH_(2b)), 4.15 (d, 1H, J=8.2 Hz, Ph—C—CH_(2a)), 4.04 (m, 2H,Ph—C—CH_(2b), Ph—N—CH_(2a)), 3.79 (t, 1H, J=6.7 Hz, J=9.1 Hz,PH—N—CH_(2b)), 3.67 (m, 4H, NH—CH ₂s, O—CH₂s), 3.34 (s, 3H, OCH₃), 2.36(qrt, 2H, J=6.2 Hz, O—(CH₂)—CH ₂s), 2.03 (s, 3H, O═C—CH₃), 1.61 (s, 3H,Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.5, 171.1, 162.5 (d, J_(CF)=246Hz), 154.2, 138.1, (d, J_(CF)=11 Hz), 128.5 (d, J_(CF)=15 Hz), 127.3 (d,J_(CF)=6 Hz), 113.4, 106.5 (d, J_(CF)=28 Hz), 72.0, 68.4, 61.6, 58.9,47.5, 41.9, 35.6, 32.2, 28.6, 23.1; HRMS Calcd for C₂₀H₂₆N₃O₅F₁:407.1856 Found: 407.1855.

EXAMPLE 8(S)-N-[[3-[3-Fluoro-4-[1-(3-hydroxypropionyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

A 10 mL recovery flask equipped with magnetic stirrer was charged with241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 1.5 mL water then cooled to 0° C. The colorless butslightly opaque solution was treated with 52 μL β-propiolactone (0.75mmol) with not observeable change. The cooling bath was removed and thereaction mixture was warmed to room temperature for two hours. Thevisually unchanged reaction mixture was diluted with 10 mL brine andextracted twice with dichloromethane (20 mL). The combined organics weredried over MgSO₄, filtered, and concentrated to give 232 mg of anoff-white foam. This crude material was purified by LC on 17 g (230-400)silica gel eluting with 7% methanol/dichloromethane to afford 178 mg(60%) the title compound as a white amorphous solid. R_(f)0.30 (10%methanol/dichloromethane); [α]_(D) −19°(c 0.9248, methanol); IR (mull)3288, 1754, 1630, 1554, 1517, 1436, 1412, 1289, 1227, 1193, cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 7.46 (dd, 1H, J=2.1 Hz, J=13.0 Hz, aromatic), 7.14(dd, 1H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.07 (t, 1H, J=8.6 Hz,aromatic), 6.55 (bt, 1H, J=6 Hz, NH), 4.81 (m, 1H, methine), 4.41 (d,1H, J=8.3 Hz, Ph—C—CH_(2a)), 4.32 (d, 1H, J=9.6 Hz, Ph—C—CH_(2b)), 4.12(d, 1H, J=8.4 Hz, Ph—C—CH_(2a)), 4.05 (m, 2H, Ph—C—CH_(2b),Ph—N—CH_(2a)), 3.88 (bs, 2H, HO—CH₂s), 3.80 (dd, 1H, J=6.8 Hz, J=9.1 Hz,Ph—N—CH_(2b)) 3.67 (m, 2H, NH—CH ₂s), 3.46 (bs, 1H, HO), 2.37 (qrt, 2H,J=5.6 Hz, HO—(CH₂)—CH ₂s), 2.03 (s, 3H, O═C—CH₃), 1.63 (s, 3H,Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 172.8, 171.2, 160.3 (d, J_(CF)=246Hz), 154.1, 138.1, (d, J_(CF)=11 Hz), 128.0 (d, J_(CF)=14 Hz), 127.1 (d,J_(CF)=6 Hz), 113.3, 106.5 (d, J_(CF)=27 Hz), 72.0, 61.4, 58.8, 58.3,47.3, 41.8, 35.7, 32.9, 28.2, 23.0; HRMS Calcd for C₁₉H₂₄N₃O₅F₁:394.1778. Found: 394.1788.

EXAMPLE 9(S)-N-[[3-[3-Fluoro-4-[1-(4-oxypentanoyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

A oven-dried 10 mL round bottom flask equipped with magnetic spinbar wascharged with 241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 4 mL dichloromethane, 100 μL levulinic acid (0.98 mmol),2.16 mg EDC.HCL (1.13) 18 mg dimethylamino pyridine (0.15 mmol) andcooled to 0° C. The colorless solution was treated with 0.31 mLtriethylamine (2.25 mmol) becoming a pale yellow color. The cooling bathwas removed and the reaction mixture was warmed to room temperature over16 hours. The visually unchanged solution was diluted with 20 mL waterand extracted twice with dichloromethane (25 mL). The combined organicswere washed once with saturated sodium bicarbonate (20 mL), brine (15mL), dried over MgSO₄, filtered, and concentrated to give 332 mg of alight yellow syrup. This crude material was purified by LC on 20 g(230-400) silica gel eluting with 5% methanol/dichloromethane to afford256 mg of an off-white amorphous solid. ¹H NMR indicates this materialto be contaminated with 8%(S)-N-[[3-[3-fluoro-4-[1-(formyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidiniyl]methyl]-acetamidewhich was removed by catalytic hydrogenolysis with 26 mg 10% palladiumon carbon in 30 mL tetrahydrofuran containing ten drops concentratedhydrochloric acid. The resulting crude material was rechromatographed on15 g (230-400) silica gel eluting with 5% methanol/dichloromethane toafford 116 mg (37% overall) the title compound as a white amorphoussolid. R_(f) 0.16 (5% methanol/dichloromethane); [α]_(D) −19°(c 0.9205,methanol); IR (mull) 1754, 1716, 1631, 1548, 1517, 1440, 1411, 1227,1193, 1166 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.46 (dd, 1 H, J=2.1 Hz,J=13.0 Hz, aromatic), 7.15 (dd, 1 H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.07(t, 1 H, J=8.5 Hz, aromatic), 6.32 (bt, 1 H, J=6 Hz, NH), 4.80 (m, 1 H,methine), 4.46 (d, 1 H, J=8.1, Ph—C—CH_(2a)), 4.27 (d, 1 H, J=9.4 Hz,Ph—C—CH_(2b)), 4.19 (d, 1 H, J=8.3 Hz, Ph—C—CH_(2a)), 4.01 (m, 2 H,Ph—C—CH_(2b), Ph—N—CH_(2a)), 3.79 (dd, 1 H, J=6.8 Hz, J=9.1 Hz,Ph—N—CH_(2b)), 3.68 (m, 2 H, NH—CH ₂s), 2.80 (t, 2 H, J=6.5 Hz, CH₃CO—CH₂s), 2.35 (m, 2 H, N—CO—CH₂), 2.19 (s, 3 H, (CH₂)—CO—CH ₃), 2.03 (s, 3H, NCO—CH₃), 1.63 (s, 3 H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 207.3,172.0, 170.9, 160.5 (d, J_(CF)=246 Hz), 153.9, 137.8 (d, J_(CF)=11 Hz),128.2 (d, J_(CF)=14 Hz), 127.0 (d, J_(CF)=6 Hz), 113.1, 106.2 (d,J_(CF)=28 Hz), 71.7, 61.3, 58.6, 47.1, 41.6, 37.6, 35.5, 29.7, 28.0,24.6, 22.8; K.F. Water=1.67%. Anal. Calcd for C₂₁H₂₆N₃O₅F₁ plus 1.67%water: C, 59.13; H, 6.33; N, 9.85. Found: C, 59.04; H, 6.38; N, 9.80.HRMS Calcd for C₂₁H₂₆N₃O₅F₁: 419.1856. Found: 419.1854.

EXAMPLE 10(S)-N-[[3-[3-Fluoro-4-[1-acetyl-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

An oven-dried 25 mL round bottom flask equipped with magnetic spinbarwas charged with 75 mg (S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.23 mmol), 5 mL dichloromethane, and cooled to 0°C. The colorless butslightly opaque solution was treated with 49 μL triethylamine (0.35mmol) and 20 μL acetyl chloride (0.28 mmol) becoming a light yellowcolor. The cooling bath was removed and the reaction mixture was warmedto room temperature over three hours. The now clear yellow solution wasdiluted with 10 mL water and extracted twice with dichloromethane (20mL). The combined organics were washed once with brine (15 mL), driedover MgSO₄, filtered, and concentrated to give 96 mg of an off-whitefoam. This crude material was combined with 28900RLH-017 and purified byLC on 10 g (230-400) silica gel eluting with 7% methanol/dichloromethaneto afford 143 mg the title compound as a white amorphous solid. R_(f)0.24 (7% methanol/dichloromethane); [α]_(D) −21°(c 0.9238, methanol); IR(mull) 1754, 1646, 1631, 1552, 1517, 1435, 1413, 1288, 1227, 1193 cm⁻¹;¹H NMR (300 MHz, CDCl₃) δ 7.46 (dd, 1 H, J=2.1 Hz, J=13.1 Hz, aromatic),7.14 (dd, 1 H, J=2.2 Hz, J=8.6 Hz, aromatic), 7.07 (t, 1 H, J=8.5 Hz,aromatic), 6.40 (bt, 1 H, J=6 Hz, NH), 4.80 (m, 1 H, methine), 4.39 (d,1 H, J=7.9 Hz, Ph—C—CH_(2a)), 4.30 (d, 1 H, J=9.5 Hz, Ph—C—CH_(2b)),4.11 (d, 1 H, J=8.2 Hz, Ph—C—CH_(2a)), 4.02 (m, 2 H, Ph—C—CH_(2b),Ph—N—CH_(2a)), 3.79 (dd, 1 H, J=6.8 Hz, J=9.1 Hz, Ph—N—CH_(2b)), 3.66(m, 2 H, NH—CH₂s), 2.03 (s, 3 H, HNCO—CH ₃), 1.90 (s, 3 H, NCO—CH₃),1.62 (s, 3 H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.0, 170.8, 160.3 (d,J_(CF)=246 Hz), 154.0, 138.0 (d, J_(CF)=11 Hz), 128.2 (d, J_(CF)=14 Hz),127.1 (d, J_(CF)=6 Hz), 113.2, 106.3 (d, J_(CF)=27 Hz), 71.8, 61.7,58.7, 47.3, 41.7, 35.2, 28.1, 22.9, 18.6; K.F. Water=1.83%. Anal. Calcdfor C₁₈H₂₂N₃O₄F₁ plus 1.83% water: C, 58.41; H, 6.20; N, 11.35. Found:C, 58.43; H, 6.45; N, 11.27. HRMS Calcd for C₁₈H₂₂N₃O₄F₁: 363.1594.Found: 363.1585.

EXAMPLE 11(S)-N-[[3-[3-Fluoro-4-[1-(2-fluoroethyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

An oven-dried 10 mL recovery flask equipped with magnetic spinbar andreflux condenser was charged with 262 mg 2-fluoro-1-tosyl ethanol (1.2mmol), 321 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(1.0 mmol), 7.0 mL acetronitrile, and 415 mg powdered potassiumcarbonate (3.0 mmol). The resulting white suspension was heated toreflux for 16 hours. The visually unchanged reaction mixture was cooledto room temperature, volatiles removed in vacuo, resulting residuediluted with 20 mL water, and extracted twice with dichloromethane (20mL). The combined organics were washed once with brine (20 mL), driedover MgSO₄, filtered, and concentrated to give 394 mg of a light brownsyrup. This crude material was purified by LC on 19 g (230-400) silicagel eluting with 7% methanol/dichloromethane to afford 260 mg (71%) thetitle compound as a light peach amorphous solid. R_(f) 0.30 (7%methanol/dichloromethane); [α]_(D) −21°(c 0.95445, methanol); IR (mull)1753, 1660, 1630, 1550, 1515, 1481, 1435, 1411, 1225, 1195 cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 7.36 (dd, 1 H, J=2.2 Hz, J=12.7 Hz, aromatic), 7.11(dd, 1 H, J=2.3 Hz, J=8.5 Hz, aromatic), 6.98 (t, 1 H, J=8.6 Hz,aromatic), 6.23 (bt, 1 H, J=6 Hz, NH), 4.79 (m, 1 H, methine), 4.47 (dt,2 H, J=4.8 Hz, J_(HF)=47.4 Hz, F—CH₂), 4.04 (t, 1 H, J=9.0 Hz,Ph—N—CH_(2a)), 3.77 (dd, 1 H, J=6.8 Hz, J=9.2 Hz, Ph—N—CH_(2b)), 3.66(m, 4 H, HN—CH₂s), 3.34 (d, 2 H, J=7.2 Hz, N—CH_(2b)s), 2.75 (dt, 2 H,J=4.9 Hz, J_(HF)=28.2 Hz, F—CH₂—CH ₂), 2.03 (s, 3 H, O═c—CH₃), 1.64 (s,3 H, Ph—C—CH₃); ¹³C NMR (7 MHz, CDCl₃) 170.8, 159.9 (d, J_(CF)=245 Hz),153.9, 137.0 (d, J_(CF)=11 Hz), 131.1 (d, J_(CF)=16 Hz), 127.0 (d,J_(CF)=7 Hz), 113.2 (d, J_(CF)=3 Hz), 106.2 (d, J_(CF)28 Hz), 82.6 (d,J_(CF)=166 Hz), 71.7, 66.0, 58.5 (d, J_(CF)=19 Hz), 47.2, 41.6, 36.8,27.1, 22.8; K.F. Water=1.05%; Anal, Calcd for C₁₈H₃N₃O₃F₂ plus 1.66%water: C, 57.87; H, 6.39; N, 11.25. Found: C, 57.67; H, 6.43; N, 11.18.HRMS Calcd for C₁₈H₃N₃O₃F₂: 368.1786. Found 368.1789.

EXAMPLE 12(S)-N-[[3-[3-Fluoro-4-[1-(cyanomethyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

An oven-dried 10 mL recovery flask equipped with magnetic spinbar andreflux condenser was charged with 321 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(1.0 mmol), 7.0 mL acetronitrile, 76 μL chloroacetronitrile (1.2 mmol),and 415 mg powdered potassium carbonate (3.0 mmol). The resulting whitesuspension was heated to reflux and quickly darkened to a tan color. TLCafter 20 minutes indicates almost complete consumption of(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide,and the reaction was stirred at room temperature for 16 hours. Thevisually unchanged reaction mixture was cooled to room temperature,volatiles removed in vacuo, resulting residue diluted with 20 mL water,and extracted twice with dichloromethane (20 mL). The combined organicswere washed once with brine (20 mL), dried over MgSO₄, filtered, andconcentrated to give 340 mg of a yellow foam. This crude material waspurified by LC on 24 g (230-400) silica gel eluting with 5%methanol/dichloromethane to afford 271 mg (75%) the title compound as awhite amorphous solid. R_(f) 0.30 (5% methanol/dichloromethane); [δ]_(D)−22°(c 0.9252, methanol); IR (mull) 1752, 1661, 1631, 1546, 1516, 1480,1434, 1412, 1227, 1195 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.39 (dd, 1 H,J=2.3 Hz, J=12.8 Hz, aromatic), 7.13 (dd, 1 H, J=2.2 Hz, J=8.5 Hz,aromatic), 6.99 (t, 1 H, J=8.6 Hz, aromatic), 6.30 (bt, 1 H, J=6 Hz, NH)4.79 (m, 1 H, methine) 4.03 (t, 1 H, J=9.0 Hz, Ph—N—CH_(2a)), 3.77 (dd,1 H, J=6.8 Hz, J=9.1 Hz, Ph—N—CH_(2b)), 3.66 (m, 2 H, HN—CH₂s), 3.55 (s,4 H, N—CH₂s), 3.49 (s, 2 H, NC—CH₂), 2.02 (s, 3 H, O═C—CH₃), 1.64 (s, 3H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃); 171.1, 159.9 (d, J_(CF)=246 Hz),154.1, 137.4 (d, J_(CF)=11 Hz), 129.7 (d, J_(CF)=15 Hz), 126.9 (d,J_(CF)7 Hz), 114.8, 113.3 106.2 (d, J_(CF)=28 Hz), 71.8, 63.3, 47.2,43.9, 41.6, 36.5, 26.9, 22.8; K.F. Water=1.42%; Anal. Calcd forC₁₈H₂₁N₄O₃F₁ plus 1.42% water: C, 59.14; H, 5.95; N, 15.33. Found: C.58.96; H, 5.88; N, 15.33. HRMS Calcd for C₁₈H₂₁N₄O₃F₁: 360.1598. Found:360:1610.

EXAMPLE 13(S)-N-[[3-[3-Fluoro-4-[1-(5-nitro-2-thiazolyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

An oven-dried 10 mL round bottom flask equipped with magnetic spinbarwas charged with 241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 4 mL dimethylsulfoxide, and 188 mg 2-bromo-5-nitrothiazole. This golden homogenous solution was treated with207 mg powdered potassium carbonate (1.5 mmol) and stirred at roomtemperature for 16 hours. The now dark brown suspension was diluted with40 mL dichloromethane and washed with water (3×15 mL), once with brine(15 mL), dried over MgSO₄, filtered, and concentrated to give 280 mg ofan orange foam. This crude material was purified by LC on 18 g (230-400)silica gel eluting with 5% methanol/dichloromethane to afford 191 mg(56%) the title compound as a yellow solid. This material wasrecrystallized from ethyl acetate/hexane to afford 88 mg of a yellowsolid, mp 182-185° C. (dec.); R_(f) 0.29 (5% methanol/dichloromethane);[α]_(D) −20°(c 0.4062, DMSO); IR (mull) 1747, 1771, 1572, 1517, 1498,1475, 1439, 1282, 1228, 1199, cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.50 (dd,1 H, J=2.1 Hz, J=13.1 Hz, aromatic), 7.20 (dd, 1 H, J=2.2 Hz, J=8.5 Hz,aromatic), 7.12 (t, 1 H, J=8.5 Hz, aromatic), 4.79 (m, 1 H, methine),4.51 (d, 2 H, J=8.9, Ph—C—CH₂s), 4.24 (d, 2 H, J=9.4 Hz, Ph—C—CH₂s),4.07 (t, 1 H, J=9.0 Hz, Ph—N—CH_(2a)), 3.79 (dd, 1 H, J=7.0 Hz, J=9.5Hz, Ph—N—CH_(2b)), 3.62 (m, 2 H, NH—CH ₂s), 2.01 (s, 3 H, O═C—CH₃), 1.75(s, 3 H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 201.0, 171.9, 171.8, 160.1(d, J_(CF)=247 Hz), 154.6, 145.5, 138.4 (d, J_(CF)=11 Hz), 127.1, 126.9(d, J_(CF)=6 Hz), 113.5, 106.5 (d, J_(CF)=27 Hz), 72.2, 64.0, 47.4,41.7, 38.1, 28.0, 22.4; K.F. Water=0.59%. Anal. Calcd for C₁₉H₂₀N₅O₅F₁S₁plus 0.59% water: C, 50.48; H, 4.53; N, 15.49. Found: C, 50.26; H, 4.69;N, 15.29.

EXAMPLE 14(S)-N-[[3-[3-Fluoro-4-[1-(methanesulfonyl)-3-(3-methyl)-azetidinyl]-phenyl]-2oxo-5-oxazolidinyl]methyl]-acetamide

An oven-dried 15 mL round bottom flask equipped with magnetic spinbarwas charged with 241 mg(S)-N-[[3-[3-fluoro-4-[3-methyl3-azetidinyl]-phenyl]-2oxo-5-oxazolidinyl]methyl]-acetamide(0.75 mmol), 8 mL dichloromethane, and cooled to 0° C. The colorless butslightly opaque solution was treated with 0.16 mL triethylamine (1.1mmol) and 70 μL methanesulfonyl chloride (0.90 mmol) with no visiblechange. The cooling bath was removed and the reaction mixture was warmedto room temperature over three hours. The now clear solution wasconcentrated to a colorless syrup. This crude material was purified byLC on 18 g (230-400) silica gel eluting with 5% methanol/ethyl acetateto afford 234 mg (78%) the title compound as a white foam. R_(f) 0.30(5% methanol/ethyl acetate); [δ]_(D) −9°(c 0.9701, methanol; IR (mull)1753, 1664, 1631, 1517, 1436, 1412, 1333, 1228, 1194, 1151 cm⁻¹; ¹H NMR(300 MHz, CDCl₃) δ 7.44 (dd, 1 H, J=2.2 Hz, J=13.0 Hz, aromatic), 7.16(m, 1 H, aromatic), 7.00 (t, 1 H, J=8.6 Hz, aromatic) 6.30 (bt, 1 H, J=6Hz, NH) 4.80 (m, 1 H, methine), 4.24 (d, 2 H J=7.4 Hz, Ms—N—CH_(2a)s),4.05 (t, 1 H, J=9.0 Hz, Ph—N—CH_(2a)), 3.88 (d, 2 H, J=7.6 Hz,Ms—N—CH_(2b)s), 3.79 (m, 1 H, Ph—N—CH_(2b)), 3.66 (m, 2 H, NH—CH ₂s),2.87 (s, 3 H, S—CH₃), 2.03 (s, 3 H, O═C—CH₃), 1.68 (s, 3 H, Ph—C—CH₃);¹³C NMR (75 MHz, CDCl₃) 171.2, 160.2 (d, J_(CF)=246 Hz), 154.2, 138.3(d, J_(CF)=11 Hz), 128.2 (d, J_(CF)=15 Hz), 126.9 (d, J_(CF)=6 Hz),113.5 (d, J_(CF)=3 Hz), 106.5 (d, J_(CF)=28 Hz), 72.0, 60.8, 47.4, 41.8,36.2, 35.0, 27.4, 23.1; Melt solvate=0.3% ethyl acetate; K.F.Water=1.05%; Anal. Calcd for C₁₇H₂₂N₃O₅F₁S₁ plus 0.3% ethyl acetate and1.05% water: C, 50.59; H, 5.62; N, 10.38. Found: C, 50.50; H, 5.81; N,10.29. HRMS Calcd for C₁₇H₂₂N₃O₅F₁S₁: 400.1342. Found: 400.1352.

EXAMPLE 15(S)-N-[[3-[3-Fluoro-4-[1-(benzyloxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

An oven-dried 25 mL round bottom flask equipped with magnetic spinbarwas charged with 313 mg(S)-N-[[3-[3-fluoro-4-[3-methyl-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.97 mmol), 10 mL dichloromethane, and cooled to 0° C. The colorlessbut slightly opaque solution was treated with 0.27 mL triethylamine (2.0mmol) and 0.23 mL benzyloxyacetyl chloride (1.5 mmol) with the reactionmixture becoming clear and a pale yellow color. The cooling bath wasremoved and the reaction mixture was warmed to room temperature over 16hours. The visually unchanged solution was diluted with 15 mL saturatedsodium bicarbonate and extracted twice with dichloromethane (20 mL). Thecombined organics were washed once with 15 mL brine, dried over MgSO₄,filtered, and concentrated to give 521 mg of a light yellow foam. Thiscrude material was purified by LC on 27 g (230-400) silica get elutingwith 10% methanol/ethyl acetate to afford 370 mg (81%) the titlecompound as a white foam. R_(f) 0.29 (10% methanol/ethyl acetate);[δ]_(D) −17°(c 0.9516, methanol); IR (mull) 1754, 1654, 1631, 1548,1516, 1438, 1411, 1226, 1193, 1122 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.45(dd, 1 H, J=2.2 Hz, J=13.0 Hz, aromatic), 7.33 (m, 5 H, aromatic), 7.15(dd, 1 H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.04 (t, 1 H, J=8.6 Hz,aromatic), 6.42 (bt, 1 H, J=6 Hz, NH), 4.79 (m, 1 H, methine), 4.57 (s,2 H, Ph—CH₂), 4.50 (d, 1 H, J=9.0 Hz, Ph—C—CH_(2a)), 4.33 (d, 1 H, J=9.7Hz, Ph—C—CH_(2b)), 4.23 (d, 1 H, J=9.2 Hz, Ph—C—CH_(2b)), 4.04 (m, 4 H,Ph—C—CH_(2a), O—CH₂, Ph—N—CH_(2a)), 3.79 (dd, 1 H, J=6.8 Hz, J=9.0 Hz,Ph—N—CH_(2b)), 3.66 (m, 2 H, NH—CH₂), 2.02 (s, 3 H, O═C—CH₃), 1.61 (s, 3H, Ph—C—CH₃); ¹³C NMR (75 MHz, CDCl₃) 171.1, 169.6, 160.3 (d, J_(CF)=246Hz), 154.1, 138.1 (d, J_(CF) =11 Hz), 137.0, 128.4, 128.2, 128.0, 127.9,127.2 (d, J_(CF)=6 Hz), 113.3 106.5 (d, J_(CF)=26 Hz), 73.3, 71.9, 69.0,62.4, 59.4, 47.4, 41.8, 36.7, 28.2, 23.0; HRMS Calcd for C₂₅H₂₈N₃O₅F₁:470.2091. Found: 470.2101.

EXAMPLE 16(S)-N-[[3-[3-Fluoro-4-[1-(hydroxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

A 250 mL Parr flask was charged with a solution of 310 mg(S)-N-[[3-[3-fluoro-4-[1-(benzyloxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide(0.66 mmol) in 30 mL methanol and 31 mg 10% palladium on carbon. Theblack suspension was placed under 40 psi hydrogen with shaking for 16hours with the pressure remaining constant. The reaction was monitoredby TLC analysis with several additional equivalents of 10% palladium oncarbon (300 mg total amount) and prolonged time (five days) to fullyconsume(S)-N-[[3-[3-fluoro-4-[1-(benzyloxyacetyl)-3-(3-methyl)-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide.The reaction mixture was filtered through a pad of Celite andconcentrated to afford 221 mg (88%) the title compound as an off-whiteamorphous solid. R_(f) 0.21 (15% methanol/ethyl acetate); [δ]_(D) −20°(c0.9432, methanol); IR (mull) 1754, 1655, 1632, 1552, 1517, 1481, 1435,1412, 1227, 1192 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ 7.47 (d, 1 H, J=2.1 Hz,J=13.0 Hz, aromatic), 7.15 (dd, 1 H, J=2.2 Hz, J=8.5 Hz, aromatic), 7.07(t, 1 H, J=8.6 Hz, aromatic), 6.37 (bt, 1 H, J=6 Hz, NH), 4.80 (m, 1 H,methine), 4.38 (m, 2 H, Ph—C—CH_(2a&b)), 4.01 (m, 5 H, Ph—C—CH_(2a&b),HO—CH ₂, Ph—N—CH_(2a)), 3.79 (dd, 1 H, J=6.8 Hz, J=9.1 Ph—N—CH_(2b)),3.68 (m, 2 H, HN—CH ₂s), 2.03 (s, 3 H, O═C—CH₃), 1.65 (s, 3 H, Ph—C—CH)171.3, 170.9, 160.1 (d, J_(CH)246 Hz), 153.9, 138.1 (d, J_(CF)=11 Hz),127.6 (d, J_(CF)=14 Hz), 126.9 (d, J_(CF)=6 Hz), 113.1, 106.3 (d,J_(CF)=28 Hz), 71.8, 60.1, 59.3, 58.5, 47.1, 41.6, 37.0, 28.0, 22.8;HRMS Calcd for C₁₈H₂₂N₃O₅F₁: 379.1543. Found: 379.1542.

EXAMPLE 17(S)-(-)-N-[[2-Oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:4-Hydroxy-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester

To a solution of N-(carbobenzyloxy)-4-bromoaniline (5.00 g) in drytetrahydrofuran (80 mL) at −78° C. under N₂ is added n-butyllithium(21.4 mL, 1.6 M in hexanes) dropwise over five minutes. The resultingyellow solution is stirred at −78° C. for 30 minutes and is then treatedwith a solution of N-(carbobenzyloxy)-4-piperidone (3.99 g) in drytetrahydrofuran (17 mL). The reaction mixture is stirred for threehours, during which the reaction temperature is allowed to rise to 0°C., and is quenched with saturated aqueous ammonium chloride (30 mL).The mixture is then diluted with water (100 mL), the layers areseparated, the aqueous phase is extracted with diethyl ether, and thecombined organic phase is washed with saline (50 mL), dried overanhydrous sodium sulfate, and concentrated under reduced pressure. Theresidue is chromato-graphed on silica gel (230-400 mesh, 350 g), elutingwith ethyl acetate/hexane (25/75), and those fractions with anR_(f)=0.38 by TLC (ethyl acetate/hexane, 50/50) are pooled andcon-centrated under reduced pressure by give the title compound, mp 156°C.-158° C.

Step 2: 3,6-Dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester

A solution of4-hydroxy-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 17, Step 1, 2.50 g) in dry methylenechloride under N₂ is treated with trifluoroacetic acid (0.84 mL),stirred at ambient temperature for three hours, diluted with saturatedaqueous potassium carbonate (25 mL) to neutralize excesstrifluouroacetic acid, and the layers are separated. The organic phaseis washed with water (20 mL) and saline (20 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure, and the residueis chromatographed on silica gel (230-400 mesh, 300 g), eluting with agradient of ethyl acetate/hexane (20/80-50/50). Pooling of fractionswith an R_(f)=0.69 by TLC (ethyl acetate/hexane, 50/50) and removal ofsolvent under reduced pressure gives the title compound, mp 146-148° C.

Step 3:(R)-(-)-3,6-Dihydro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester

A solution of3,6-dihydro-4-[4-[[phenylmethoxy)carbonyl]amino]phenyl]-1-(2H)-pyridinecarboxylic acid phenylmethyl ester (EXAMPLE 17, Step 2, 0.500g) in dry tetrahydrofuran (5.7 mL) at −78° C. under N₂ is treated withn-butyllithium (0.73 mL, 1.6 M in hexanes) dropwise over five minutes.The resulting mixture is stirred at −78° C. for 45 minutes and is thentreated with (R)-(-)-glycidyl butyrate dropwise. The resulting solutionis allowed to warm to ambient temperature over approximately 45 minutesand is stirred for an additional 20 hours, after which the reaction isquenched with saturated aqueous ammonium chloride (10 mL), diluted withwater (20 mL) and extracted with ethyl acetate (2×15 mL). The combinedorganic phase is washed with saline (10 mL), dried over anhydrousmagnesium sulfate and concentrated under reduced pressure to give thecrude product which is chromatographed on silica gel (230-400 mesh, 40g), eluting with methanol/methylene chloride (1/99). Pooling andconcentration of those fractions with an R_(f)=0.37 by TLC(methanol/chloroform, 5/95) gives the title compound, mp 131.5 133.5° C.

Step 4:(R)-(-)-3,6-Dihydro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester

A solution of(R)-(-)-3,6-dihydro-4-[4-[5-(hydroxymethyl)-2oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester ( EXAMPLE 17, Step 3, 970mg) and triethylamine (0.50 mL) in dry methylene chloride (9.5 mL) at 0°C. under N₂ is treated with methanesulfonyl chloride (0.20 mL) dropwise.The resulting mixture is stirred at 0° C. for one hour, diluted withmethylene chloride (40 mL), washed with water (10 mL), saturated aqueoussodium bicarbonate (10 mL) and saline (10 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure to give the titlecompound, mp 166-168° C.

Step 5:(S)-(-)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]-3,6-dihydro-1(2H)-pyridinecarboxylic acid phenylmethyl ester

A mixture of(R)-(-)-3,6-dihydro-4-[4-[5-[[(methylsulfonyl)oxo]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester (EXAMPLE 17, Step 4, 935mg) and concentrated aqueous ammonium hydroxide (4 mL) in isopropanol (4mL) and tetrahydrofuran (4 mL) is placed in a sealed tube and immersedin an oil bath maintained at 95° C. for 18 hours. The mixture is thendiluted with methylene chloride (40 mL), washed with saline (20 mL),dried over anhydrous sodium sulfate and concentrated under reducedpressure to give the 5-aminomethyl-2-oxazolidinone intermediate(R_(f)=0.34 by TLC, methanol/chloroform, 10/90). A solution of thisintermediate (783 mg) and pyridine (1.55 mL) in dry methylene chloride(19 mL) at 0° C. under N₂ is treated with acetic anhydride (0.90 mL),and the resulting solution is allowed to warm to ambient temperaturewith stirring over 1.5 hours. The mixture is then diluted with methylenechloride (20 mL), washed with water (10 mL), saturated aqueous sodiumbicarbonate (2×10 mL) and saline (10 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the crudeproduct which is chromatographed on silica get (230-400 mesh, 75 g),eluting with a gradient of methanol/methylene chloride (1/99-2/98).Pooling and concentration of those fractions with an R_(f)=0.26 by TLC(methanol/chloroform, 5/95) gives the title compound, mp 166-169° C.

Step 6:(S)-(-)-N-[[2-Oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]-3,6-dihydro-1(2H)-pyridinecarboxylic acid phenylmethyl ester (EXAMPLE 17, Step 5, 625mg) and 10% palladium-on-carbon (300 mg) in methanol (100 mL) is shakenon a Parr apparatus under a hydrogen atmosphere at 40 psi for one hourand at 20 psi for 16 hours, the catalyst is removed by filtrationthrough Celite and the filtrate is concentrated under reduced pressureto give the title compound, mp 169-171° C.

EXAMPLE 18(S)-(-)-N-[[3-[4-[1-[(Benzyloxy)acetyl]-4-piperidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 17, 300 mg) and triethylamine (0.20 mL) in dry methylenechloride (19 mL) at 0° C. under N₂ is treated with benzyloxyacetylchloride (0.18 mL), and the resulting solution is stirred at 0° C. forone hour and at ambient temperature for one hour. The reaction mixtureis then washed with water (2×10 mL), saturated aqueous sodiumbicarbonate (10 mL) and saline (10 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the crudeproduct which is chromatographed on silica gel (230-400 mesh, 45 g),eluting with a gradient of methanol/methylene chloride (1/99-2/98).Pooling and concentration of those fractions with an R_(f)=0.28 by TLC(methanol/chloroform, 5/95) gives the title compound, NMR (CDCl₃, 400MHz) 7.45, 7.35, 7.18, 6.26, 4.75, 4.63, 4.22, 4.04, 3.78, 3.70, 3.60,3.09, 2,70, 2.02, 1.85, 1.60 δ.

EXAMPLE 19(S)-(-)-N-[[3-[4-[1-(Hydroxyacetyl)-4-piperidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-N-[[3-[4-[1-[(benzyloxy)acetyl]-4-piperidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 18, 207 mg) and 10% palladium-on-carbon (100 mg) in methanol(9mL) is shaken on a Parr apparatus under a hydrogen atmosphere at 40psi for 20 hours, the catalyst is removed by filtration through Celiteand the filtrate is concentrated under reduced pressure to give thecrude product which is chromatographed on silica gel (230-400 mesh, 20g), eluting with a gradient of methanol/methylene chloride (5/95-10/90).Pooling and concentration of those fractions with an R_(f)=0.26 by TLC(methanol/chloroform, 10/90) and recrystallization from methylenechloride/diethyl ether gives the title compound, mp 155-157° C.

EXAMPLE 20(S)-(-)-N-[[2-Oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:1-(3-Fluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane

A solution of freshly distilled diisopropylamine (22.9 mL) in drytetrahydrofuran (175 mL) at −78° C. under N₂ is treated withn-butyllithium (1.6 M in hexanes, 109 mL) dropwise over 15 minutes, andthe resulting mixture is stirred at −78° C. for 45 minutes and is thenadded over ten minutes via cannula to a solution of 3-fluoroaniline(8.00 mL) in dry tetrahydrofuran (166 mL) at −78° C. under N₂. Theresulting reaction mixture is stirred at −78° C. for 50 minutes and isthen treated with a solution of1,1,4,4-tetramethyl-1,4-dichlorodisilethylene (18.3 g) in drytetrahydrofuran (85 mL). The mixture is allowed to slowly warm toambient temperature over four hours with stirring and is then washedwith water (2×200 mL) and saline (100 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the titlecompound, NMR (CDCl₃, 400 MHz) 7.12, 6.65, 6.58, 0.86, 0.24 δ.

Step 2: 3,6-Dihydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylic acid 1,1-dimethylethyl ester

A solution of freshly distilled diisopropylamine (8.70 mL) in drytetrahydrofuran (133 mL) at −78° C. under N₂ is treated withn-butyllithium (1.6 M in hexanes, 41.5 mL) dropwise over ten minutes,and the resulting mixture is stirred at −78° C. for one hour and is thentreated with a solution of 1-(1,1-dimethylethoxycarbonyl)-4-piperidone(12.0 g) in dry tetrahydrofuran (120 mL) dropwise over 10 minutes. Theresulting mixture is stirred at −78° C. for 40 minutes and is thentreated with a solution of N-phenyltrifluoromethanesulfonimide (22.0 g)in dry tetrahydrofuran (62 mL) over five minutes. The reaction mixtureis stirred at −78° C. for 10 minutes and at 0° C. for four hours and isthen quenched with water (200 mL). The layers are separated, the aqueousphase is extracted with diethyl ether (100 mL) and the combined organicphase is washed with saline (50 mL), dried over anhydrous magnesiumsulfate and concentrated under reduced pressure to give the titlecompound, NMR (CDCl₃, 400 MHz) 5.77, 4.05, 3.64, 2.45, 1.48 δ.

Step 3: 3,6-Dihydro-4-[4-amino-2-fluorophenyl]-1(2 H)-pyridinecarboxylicacid 1,1-dimethylethyl ester

A solution of1-(3-fluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane(EXAMPLE 20, Step 1, 19.1 g) in dry tetrahydrofuran (150 mL) at −78° C.under N₂ is treated with sec-butyllithium (1.3 M in cyclohexane, 60.3mL) dropwise over ten minutes, and the resulting mixture is stirred at−78° C. for 2.25 hours. A solution of zinc chloride (0.5 M intetrahydrofuran, 150 mL) is then added over 15 minutes, and the mixtureis allowed to warm to ambient temperature over one hour with stirring. Asolution of 3,6-dihydro-4-[[(trifluoromethyl)-sulfonyl]oxy]1(2H)-pyridinecarboxylic acid 1,1-dimethylethyl ester (EXAMPLE 20, Step, 2,20.8 g) in dry tetrahydrofuran (63 mL) andtetrakis(triphenylphosphine)palladium(0) (1.45 g) is added, and themixture is degassed, heated up to reflux, refluxed for five minutes,cooled to ambient temperature and stirred for 12 hours. The mixture isthen diluted with water (150 mL), the layers are separated, the aqueousphase is extracted with diethyl ether (2×100 mL) and the combinedorganic phase is washed with water (100 mL) and saline (100 mL), driedover anhydrous magnesium sulfate and concentrated under reducedpressure. The residue is then dissolved in methanol (630 mL) and treatedwith anhydrous potassium carbonate (17.3 g), and the mixture is stirredat ambient temperature for 40 minutes, concentrated under reducedpressure, diluted with water (100 mL) and extracted with diethyl ether(2×150 mL). The combined organic phase is washed with water (50 mL) andsaline (50 mL), dried over anhydrous magnesium sulfate and concentratedunder reduced pressure to give the crude product which ischromatographed on silica gel (230-400 mesh, 1 kg), eluting with agradient of ethyl acetate/hexane (15/85-50/50). Pooling andconcentration of those fractions with an R_(f)=0.17 by TLC (ethylacetate/hexane, 26/75) gives the title compound, mp 123-125° C.

Step 4:4-[4-[[(Phenylmethoxy)carbonyl]amino-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

A mixture of3,6-dihydro-4-[4-amino-2-fluorophenyl]-1(2H)-piperidinecarboxylic acid

1,1-dimethylethyl ester (EXAMPLE 20, Step 3, 11.44 g) and 10%palladium-on-carbon (4 g) in methanol (400 mL) in four Parr bottles isshaken on the Parr apparatus under a hydrogen atmosphere at 40 psi fortwo hours, the catalyst is removed by filtration through Celite, and thefiltrate is concentrated under reduced pressure to give the4-[4-amino-2-fluorophenyl]-1-piperidinecarboxylic add 1,1-dimethylethylester intermediate. A mixture of this intermediate (11.17 g) and sodiumbicarbonate (6.57 in dry tetrahydrofuran (390 mL) is treated with benzylchloroformate (5.86 mL), and the resulting mixture is stirred at ambienttemperature for 15 hours and washed with water (200 mL). The aqueousphase is extracted with methylene chloride (150 mL), and the combinedorganic phase is washed with saline (50 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the crudeproduct which is chromatographed on silica gel (70-230 mesh, 800 g),eluting with a gradient of ethyl acetate/hexane (15/85-25/75). Poolingand concentration of those fractions with an R_(f)=0.38 by TLC (ethylacetatethexane, 25/75) gives the title compound, mp 96-98° C.

Step5:(R)-(-)4-[4-[5-(Hydroxymethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

A solution of4-[4-[[(phenylmethoxy)carbonyl]amino-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 20, Step 4, 0.500 g) in drytetrahydrofuran (5.7 mL) at −78° C. under N₂ is treated withn-butyllithium (0.73 mL, 1.6M in hexanes) dropwise over five minutes.The resulting mixture is stirred at −78° C. for 45 minutes and is thentreated with (R)-(-)-glycidyl butyrate dropwise. The resulting solutionis allowed to warm to ambient temperature over approximately 45 minutesand is stirred for an additional 20 hours, after which the reaction isquenched with saturated aqueous ammonium chloride (10 mL), diluted withwater (20 mL) and extracted with ethyl acetate (2×15 mL). The combinedorganic phase is washed with saline (10 mL), dried over anhydrousmagnesium sulfate and concentrated under reduced pressure to give thecrude product which is chromatographed on silica gel (230-400 mesh, 40g), eluting with methanol/methylene chloride (1/99). Pooling andconcentration of those fractions with an R_(f)=0.37 by TLC(methanol/chloroform, 5/95) gives the title compound, mp 120-122° C.

Step 6:(R)-(-)-4-[4-[5-[](Methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

A solution of(R)-(-)-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 20, Step 5, 970 mg) andtriethylamine (0.50 mL) in dry methylene chloride (9.5 mL) at 0° C.under N₂ is treated with methanesulfonyl chloride (0.20 mL) dropwise.The resulting mixture is stirred at 0° C. for one hour, diluted withmethylene chloride (40 mL), washed with water (10 mL), saturated aqueoussodium bicarbonate (10 mL) and saline (10 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure to give the titlecompound, mp 163-165° C.

Step 7:(R)-(-)-4-[4-[5-(Azidomethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicadd 1,1-dimethylethyl ester

A mixture of(R)-(-)-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylic acid 1,1-dimethylethyl ester(EXAMPLE 20, Step 6, 13.83 g) and sodium azide (7.62 g) in drydimethylformamide (117 mL) under N₂ is stirred at 60° C. for five hoursand at ambient temperature for 16 hours. The mixture is then dilutedwith ethyl acetate (200 mL), washed with water (8×100 mL) and saline(100 mL), dried over anhydrous magnesium sulfate and concentrated underreduced pressure to give the title compound, mp 109-110° C.

Step 8:(S)-(-)-4-[4-[5-(Aminomethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

A solution of(R)-(-)4-[4-[5-(azidomethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 20, Step 7, 12.05 g) in drytetrahydrofuran (96 mL) under N₂ is treated with triphenylphosphine(8.29 g) over five minutes, and the resulting mixture is stirred atambient temperature for two hours. The mixture is then treated withwater (3.1 mL), heated up to 40° C., stirred at 40° C. for five hoursand at ambient temperature for 12 hours, and then concentrated underreduced pressure to give a viscous oil which is chromatographed onsilica gel (70-230 mesh, 500 g), eluting with a gradient ofmethanol/methylene chloride (2.5/97.5-15/85). Pooling and concentrationof those fractions with an R_(f)=0.26 BY TLC (methanol/chloroform,10/90) gives the title compound, mp 136—137° C.

Step 9:(S)-(-)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

A solution of(S)4-)-4-[4-[5-(aminomethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 20, Step 8, 9.45 g) in drymethylene chloride (96 mL) under N₂ is treated with pyridine (5.82 mL)and acetic anhydride (3.40 mL), and the resulting mixture is stirred atambient temperature for four hours, diluted with methylene chloride (25mL), washed with water (25 mL), saturated aqueous sodium bicarbonate (25mL) and saline (25 mL), dried over anhydrous sodium sulfate andconcentrated under reduced pressure to give the crude product which isthen chromatographed on silica gel (230-400 mesh, 350 g), eluting with agradient of methanol/chloroform (2.5/97.5-7.5/92.5). Pooling andconcentration of those fractions with an R_(f)=0.51 by TLC(methanol/chloroform, 10/90) gives the title compound, mp 144-146° C.

Step 10:(S)-(-)-N-[[2-Oxo-3-[4-[4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide

A solution of(S)-(-)-4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 20, Step 9, 10.44 g) in dry methylenechloride (100 mL) at 0° C. under N₂ is treated with trifluoroacetic acid(24.0 mL) over one minute, and the resulting mixture is stirred at 0° C.for 1.75 hours, concentrated under reduced pressure, diluted with water(100 mL), cooled in an ice bath, adjusted to pH 11 with saturatedaqueous potassium carbonate, and extracted with methanol/methylenechloride (5/95, 6×100 mL). The combined organic phase is dried overanhydrous sodium sulfate and concentrated under reduced pressure to givethe title compound, mp 163-164° C.

EXAMPLE 21(S)-(-)-N-[[3-[4-[1-[(Benzyloxy)acetyl]-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]-acetamide(EXAMPLE 20,) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]-methyl]acetamideand purifying the crude product by trituration with chloroform/diethylether and filtration, the title compound is obtained, mp 147-149° C.

EXAMPLE 22(S)-(-)-N-[[3-[-4-[1-(Hydroxyacetyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-N-[[3-[4-[1-[(benzyloxy)acetyl]-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 21, 5.00 g) and 20% palladium hydroxide on carbon (2.80 g) inmethanol (500 mL) is stirred under a hydrogen atmosphere (balloon) forfour hours, the catalyst is removed by filtration through Celite and thefiltrate is concentrated under reduced pressure, triturated withmethylene chloride/diethyl ether and filtered to give the titlecompound, mp 182-183° C.

EXAMPLE 23(S)-(-)-N-[[3-[4-[1-(Indole-2-carbonyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A solution of indole-2-carboxylic add (79 mg) and1,1′-carbonyldiimidazole (80 mg) in dry tetrahydrofuran (2.0 mL) isstirred at ambient temperature for one hour, and a solution of(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 150 mg) in dry tetrahydrofuran (6.0 mL) is added. Themixture is then stirred at ambient temperature for 19 hours,concentrated under reduced pressure, diluted with methylene chloride (20mL), washed with saturated aqueous sodium bicarbonate (10 mL), water (10mL) and saline (10 mL), dried over anhydrous sodium sulfate andconcentrated under reduced pressure to give the crude product which ischromagraphed on silica gel (70-230 mesh, 10 g), eluting withmethanol/methylene chloride (7.5/92.5). Pooling and concentration ofthose fractions with an R_(f)=0.67 by TLC (methanol/chloroform, 10/90)and recrystallization from chloroform/diethyl ether gives the titlecompound, mp 223-225° C.

EXAMPLE 24(S)-(-)-N-[[3-[4-[1-(Isoxazole-5-carbonyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A solution of isoxazole-5-carboxylic add (79 mg) and1,1′-carbonyldiimidazole (80 mg) in dry tetrahydrofuran (2.0 mL) isstirred at ambient temperature for one hour, and a solution of(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamideEXAMPLE 20, 160 mg) in dry tetrahydrofuran (6.0 mL) is added. Themixture is then stirred at ambient temperature for 19 hours,concentrated under reduced pressure, diluted with methylene chloride (20mL), washed with saturated aqueous sodium bicarbonate (10 mL), water (10mL) and saline (10 mL), dried over anhydrous sodium sulfate andconcentrated under reduced pressure to give the crude product which ischromagraphed on silica gel (70-230 mesh, 10 g), eluting withmethanoymethylene chloride (7.5/92.5). Pooling and concentration ofthose fractions with an R_(f)=0.67 by TLC (methanol/chloroform, 10/90)and recrystauization from chloroform/diethyl ether gives the titlecompound, mp 290-292° C.

EXAMPLE 25(S)-(-)-N-[[3-[4-[1-(Methylsulfonyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A solution of(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 125 mg) and pyridine (60 μL) in dry methylene chloride (1.9mL) at 0° C. is treated with methanesulfonyl chloride (32 μL), and theresulting mixture was stirred at 0° C. for one hour and at ambienttemperature for 16 hours. The reaction mixture is then diluted withmethylene chloride (30 mL), washed with water (10 mL) and saline (10mL), dried over anhydrous sodium sulfate and concentrated under reducedpressure, and the residue is recrystallized from methylenechloride/diethyl ether to give the title compound, mp 240-242° C.

EXAMPLE 26(S)-(-)-4-[4-[5-[)Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid methyl ester

A mixture of(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 150 mg) and sodium bicarbonate (75 mg) in drytetrahydrofuran (6 mL) at 0° C. under N₂ is treated with methylchloroformate (38 μL), and the resulting mixture is stirred at 0° C. forone hour. The reaction is then diluted with ethyl acetate (20 mL),washed with water (10 mL) and saline (10 mL), dried over anhydrousmagnesium sulfate and concentrated under reduced pressure, and theresidue is recrystallized from methylene chloride/diethyl ether to givethe title compound, mp 165-166° C.

EXAMPLE 27(S)-(-)-N-[-3-[4-[1-(Cyanomethyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 150 mg), chloroacetonitrile (31 μL) and anhydrous potassiumcarbonate (124 mg) in dry acetonitrile (4 mL) under N₂ was stirred atambient temperature for 20 hours, diluted with methylene chloride (20mL), washed with water (10 mL) and saline (10 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure, and the residueis recrystallized from methylene chloride/diethyl ether to give thetitle compound, mp 165-167° C.

EXAMPLE 28(S)-(-)-N-[[3-[4-[1-(2-Fluorophenyl)-4-piperidinyl]-3-fluorophenyl]-5-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 27, and making non-criticalvariations but substituting 2-fluoroethyl 4-toluenesulfonic acid esterfor chloroacetonitrile and purifying the crude product by chromatographyon silica gel (70-230 mesh, 30 g), eluting with methanoymethylenechloride, the title compound is obtained, mp 155-157° C.

EXAMPLE 29(S)-(-)-N-[[3-[4-[1-(Formyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-%-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-3-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 150 mg), 1-(3-dimethylaminopropyl)-3-ethylcarbidehydrochloride (171 mg) and formic add (34 μL) in dry tetrahydrofuran (6mL) is stirred at ambient temperature for one hour, diluted withmethylene chloride (10 mL), washed with water (10 mL) and saline (10mL), dried over anhydrous sodium sulfate and concentrated under reducedpressure, and the residue is recrystallized from methylenechloride/diethyl ether to give the title compound, mp 180-187° C.

EXAMPLE 30(S)-(-)-4-[4-[5-[[2,2-Dichloroacetyl)amino]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethyl ester

A solution of(S)-(-)-49-[4-[5-(aminomethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 20, Step 8, 400 mg) in drymethylene chloride (4.1 mL) at 0° C. under N₂ is treated withtriethylamine (0.21 mL) and dichloroacetyl chloride (0.11 mL), and theresulting mixture is stirred at 0° C. for three hours, diluted withmethylene chloride (10 mL), washed with water (10 mL), saturated aqueoussodium bicarbonate (10 mL) and saline (10 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure to give the crudeproduct which is then chromatographed on silica gel (70-230 mesh, 50 g),eluting with methanol/chloroform (5/95). Pooling and concentration ofthose fractions with an R_(f)=0.53 by TLC (methanol/chloroform, 10/90),trituration with methylene chloride/diethyl ether and filtration givesthe title compound, mp 168-170° C.

EXAMPLE 31(S)-(-)-2,2-Dichloro-N-[[2-oxo-3-[3-fluoro-4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 20, Step 10), and makingnon-critical variations but substituting(S)-(-)-4-[4-[5-[[(2,2-dichloroacetyl)amino]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1dimethylethyl ester (EXAMPLE 30) for(S)-(-)4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicadd phenylmethyl ester, the title compound is obtained, NMR (CDCl₃, 400MHz) 7.37, 7.22. 7.10, 5.99, 5.29. 4.83, 4.07, 3.78, 3.71, 3.30, 2.98,2.83, 2.09, 1.81 δ.

EXAMPLE 32(S)-(-)-2,2-Dichloro-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting(S)-(-)-2,2-dichloro-N-[[2-oxo-3-[3-fluoro-4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 31) for(S)-(-)-3-N-[4-(4-piperidinyl)phenyl]-5-acetamidomethyl-2-oxazolidinoneand acetoxyacetyl chloride for benzyloxyacetyl chloride, the titlecompound is obtained, NMR (CDCl₃, 400 MHz) 7.42, 7.15, 6.24, 4.77, 4.04,3.77, 3.68, 3.20, 3.07, 2.71, 2.20 2.02, 1.88, 1.69 δ.

EXAMPLE 33(S)-(-)-2,2-Dichloro-N-[[2-oxo-3-[fluoro-4-[1-(hydroxyacetal)-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-2,2-dichloro-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 32, 110 mg) and anhydrous potassium carbonate (60 mg) inmethanol (8.8 mL) is stirred under N₂ at ambient temperature for onehour and then concentrated under reduced pressure and chromatographed onsilica gel (70-230 mesh, 10 g), eluting with methanol/chloroform(10/90). Pooling and concentration of those fractions with an R_(f)=0.41by TLC (methanol/chloroform, 10/90), repurification by radialchromatography (2000 μ silica gel plate) eluting with methanol/methylenechloride, and trituration with chloroform/diethyl ether gives the titlecompound, NMR (CDCl₃, 400 MHz) 7.46, 7.39, 7.15, 5.99, 4.84, 4.74, 4.22,4.09, 3.77, 3.61, 3.10, 2.79, 1.89, 1.65 δ.

EXAMPLE 34(S)-(-)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-4-piperidinyl]phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20,) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamideand acetoxyacetyl chloride for benzyloxyacetyl chloride, the titlecompound is obtained, NMR (CDCl₃, 400 MHz) 7.42, 7.15, 6.24, 4.77, 4.04,3.77, 3.68, 3.20, 3.07, 2.71, 2.20, 2.02, 1.88, 1.68 δ.

EXAMPLE 35(S)-(-)-N-[[2-Oxo-3-[4-(4-piperidinyl)-3,5-difluorophenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:1-(3,5-Difluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane

Following the general procedure of Step 1 of EXAMPLE 20, and makingnon-critical variations but substituting 3,5-difluoroaniline for3-fluoroaniline, the title compound is obtained, NMR (CDCl₃, 400 MHz)6.38, 6.31, 0.87, 0.17 δ.

Step 2:3,6-Dihydro-4-[4-amino-2,6-difluorophenyl]-1(2H)-piperidinecarboxylicacid 1,1-dimethyl ester

Following the general procedure of Step 3 of EXAMPLE 20, and makingnon-critical variations but substituting1-(3,5-difluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane(EXAMPLE 35, Step 1) for1-(3-fluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disflacyclopentane, thetitle compound is obtained, mp 134-135° C.

Step 3:4-[4-[[(Phenylmethoxy)carbonyl]amino-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethyl ester

Following the general procedure of Step 4 of EXAMPLE 20, and makingnon-critics variations but substituting3,6-dihydro-4-[4-amino-2,6-difluorophenyl]-1(2H)-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 35, Step 2) for3,6-dihydro-4-[4-amino-2-fluorophenyl]-1(2H)-piperidinecarboxylic acid1,1-dimethylethyl ester and purifying the crude product by triturationwith ethyl acetate/hexane and filtration, the title compound isobtained, mp 153-155° C.

Step 4:(R)-(-)-4-[4-[5-(Hydroxymethyl)-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

Following the general procedure of Step 3 of EXAMPLE 17, and makingnon-critical critical variations but substituting4-[4-[[(phenylmethoxy)carbonyl]amino-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 35, Step 3) for3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-piperidinecarboxylicacid phenylmethyl ester, the title compound is obtained, NMR (CDCl₃, 400MHz) 7.11, 4.75, 4.22, 3.96, 3.75, 3.06, 2.76, 2.50, 1.98, 1.65, 1.48 δ.

Step 5:(R)-(-)-4-[4-[5-[[)Methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

Following the general procedure of Step 4 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(-)-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 35, Step 4) for(R)-(-)-3,6-dihydro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-piperidinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 125-126° C.

Step 6: (R)-(-)-4-[4-[5-(Azidomethyl)-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester

Following the general procedure of step 7 of EXAMPLE 20, and makingnon-critical variations but substituting(R)-(-)-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 35, Step 5) for(R)-(-)-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, mp125-127° C.

Step 7:(S)-(-)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylic1,1-dimethylethyl ester

A mixture of(R)-(-)-4-[4-[5-(azidomethyl)-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 35, Step 6, 1.51 g) and 10%palladium on carbon (367 mg) in methanol (35 mL) is stirred under ahydrogen atmosphere (balloon) for 18 hours, the catalyst is removed byfiltration through Celite and the filtrate is concentrated under reducedpressure to give the 5-aminomethyl-2-oxazolidinone intermediate(R_(f)=0.10 by TCL, methanol/chloroform, 5/95). A solution of thisintermediate (1.28 g) and pyridine (2.51 mL) in dry methylene chloride(31 mL) at 0° C. under N₂ is treated with acetic anhydride (1.47 mL),and the resulting solution is allowed to warm to ambient temperaturewith stirring over 1.5 hours. The is then diluted with methylenechloride (16 mL), washed with water (10 mL), saturated aqueous sodiumbicarbonate (2×10 mL) and saline (10 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the crudeproduct which is chromatographed on silica gel (70-230 mesh, 150 g),eluting with a gradient of methanol/methylene chloride (1/99-4/96).Pooling and concentration of those fractions with an R_(f)=0.31 by TLC(methanol/chloroform, 5/95), trituration with diethyl ether andfiltration gives the title compound, NLMR (CDCl₃, 400 MHz) 7.06, 6.56,4.78, 4.22, 4.00, 3.74, 3.65, 3.05, 2.75, 2.02, 1.96, 1.64, 1.47 δ.

Step 8:(S)-(-)-N-[[2-Oxo-3-[4-(4-piperidinyl)-3,5-difluorophenyl]-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2,6-difluorophenyl]-1-piperidinecarboxylic1,1-dimethylethyl ester (EXAMPLE 35, Step 7, 847 mg) and trifluoroaceticadd (12 mL) maintained at 0° C. under N₂ is stirred for two hours andthen concentrated under reduced pressure to remove excesstrifluoroacetic acid. The residue is diluted with saturated aqueouspotassium carbonate (70 mL) and methylene chloride (50 mL), and thelayers are separated. The aqueous phase is extracted with methylenechloride (2×50 mL), and the combined organic phase is dried overanhydrous sodium sulfate, concentrated under reduced pressure,triturated with diethyl ether and recrystallized from ethyl acetate togive the title compound, NMR (CDCl₃, 400 MHz) 7.08, 6.10, 4.78, 4.00,3.74, 3.64, 3.19, 3.07, 2.72, 2.03, 1.99, 1.68 δ.

EXAMPLE 36(S)-(-)-N-[[3-[4-[1-[(Benzyloxy)acetyl]-4-piperidinyl]-3,5-difluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3,5-difluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 35) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 169° C.-171° C.

EXAMPLE 37(S)-(-)-N-[[3-[4-[1-(Hydroxyacetyl)-4-piperidinyl]-3,5-difluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(-)-N-[[3-[4-(1-[(benzyloxy)acetyl]-4-piperidinyl]-3,5-difluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 36, 207 mg) and 10% palladium-on-carbon (100 mg) in methanol (9mL) is shaken on a Parr apparatus under a hydrogen atmosphere at 40 psifor 20 hours, the catalyst is removed by filtration through Celite andthe filtrate is concentrated under reduced pressure to give the crudeproduct which is chromatographed on silica gel (230-400 mesh, 20 g),eluting with a gradient of methanol/methylene chloride (5/95-10/90).Pooling and concentration of those fractions with an R_(f)=0.26 by TLC(methanol/chloroform, 10/90) and recrystallization from methylenechloride/diethyl ether gives the title compound, NMR (CDCl₃, 400 MHz)7.07, 6.80, 4.78, 4.69, 4.18, 3.99, 3.74, 3.63, 3.60, 3.16, 3.06, 2.90,2.72, 2.00, 1.97, 1.75 δ.

EXAMPLE 38(S)-(−)-N-[[2-Oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:(S)-(−)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester

A mixture of(S)-(−)-N-[[3-[4-trimethylstannyl-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(690 mg),3,6-dihydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester (step 2 of EXAMPLE 20, 500mg),tris(dibenzylideneacetone)dipalladium(0) (14 mg) and triphenylarsine (37mg) in N-methyl-2-pyrrolidinone (7.5 mL) is degassed, stirred under N₂at ambient temperature for 4.5 days, diluted with ethyl acetate, washedwith water (3×40 mL) and saline (20 mL), dried over anhydrous magnesiumsulfate and concentrated under reduced pressure. The residue ischromatographed on silica gel (230-400 mesh, 120g), eluting with agradient of methanol/methylene chloride (1/99-2/98), and those fractionhaving an R_(f)=0.27 by TLC (methanol/chloroform, 2×5/95) are pooled andconcentrated to give the title compound, ¹H NMR (CDCl₃, 400 MHz) 7.39,7.22, 7.13, 7.01, 5.92, 4.82, 4.06, 3.80, 3.67, 3.61, 2.47, 2.03, 1.49δ.

Step 2:(S)-(1)-N-[[2-Oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide

A solution of(S)-(−)-4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 38, Step 1, 1.00 g) in drymethylene chlordie (9.2 mL) at 0° C. under N₂ is treated withtrifluoroacetic acid (2.3 mL) over one minute, and the resulting mixtureis stirred at 0° C. for three hours and added slowly to saturatedaqueous potassium carbonate (30 mL) to neutralize excess trifluoroaceticacid. The resultant slurry is filtered and the precipitate ischromatographed on silica gel (70-230 mesh, 60 g), eluting with ammoniumhydroxide/methanol/methylene chloride (0.25/19.75/80). Those fractionswith an R_(f)=0.08 by TLC (methanol/chloroform, 20/80) are pooled andconcentrated under reduced pressure to give the title compound, ¹H NMR(MeOH-d₄, 400 MHz) 7.47, 7.33, 7.25, 6.02, 4.80, 4.15, 3.83, 3.58, 3.47,3.04, 2.46, 1.98 δ.

EXAMPLE 39(S)-(−)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting (S)-(−)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide (EXAMPLE38) for(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamideand acetoxyacetyl chloride for benzyloxyacetyl chloride, the titlecompound is obtained, mp 188-191° C.

EXAMPLE 40(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-3,6-dihydro-2H-pyridin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(−)-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 39, 475 mg) and anhydrous potassium carbonate (303 mg) inmethanol (44 mL) is stirred under N₂ at ambient temperature for 1.5hours and then adjusted to pH 7 with aqueous hydrochloric acid (1M) andconcentrated under reduced pressure. The residue is chromatographed onsilica gel (230-400 mesh, 40 g), eluting with a gradient ofmethanol/chloroform (5/95-10/90), and those fractions with an R_(f)=0.21by TLC (methanol/chloroform, 10/90) are pooled and concentrated underreduced pressure. The resulting foam is then triturated with methylenechloride/diethyl either and the precipitate filtered to give the titlecompound, Anal. calcd for C₁₉H₂₂N₈O₅F: C, 58.31;H, 5.67; N, 10.74.Found: C, 58.15; H, 5.64; N, 10.72.

EXAMPLE 41(5S)-N-[[3-[3-Fluoro-4-[1-(phenylmethyl)-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1:(S)-(−)-N-[[3-[4-Ethenyl-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(−)-N-[[3-[4-iodo-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(5.45 g), vinyltributyltin (5.48 g) andbis(triphenylphosphine)palladium(II) chloride (303 mg) in 1,4-dioxane(72 mL) under N₂ is degassed, heated up to reflux, refluxed for sevenhours, cooled to ambient temperature and stirred for 12 hours. Themixture is then diluted with ethyl acetate (40 mL) and water (50 mL) andthe layers are separated. The aqueous phase is extracted with ethylacetate (2×30 mL), and the combined organic phase is washed with saline(40 mL), dried over anhydrous magnesium sulfate, concentrated underreduced pressure and triturated with diethyl ether. The resultantprecipitate is filtered to five the title compound, mp 165-166° C.

Step 2:(5S)-N-[[3-[3-[3-Fluoro-4-[1-(phenylmethyl)-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A solution of(S)-(−)-N-[[3-[4-vinyl-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 41, Step 1, 3.50 g) and trifluoroacetic acid (0.23 mL) in drymethylene chloride under N₂ is treated with a solution ofN-benzyl-N-(methoxymethyl) trimethylsilylmethylamine (6.10 g) in drymethylene chloride (50mL) dropwise over 4.5 hours, and the resultingsolution was stirred at ambient temperature for 17 hours. The reactionmixture is then washed and saturated aqueous sodium bicarbonate (30 mL),water (30 mL) and saline (30 mL), dried over anhydrous sodium sulfateand concentrated under reduced pressure to give a residue which ischromatographed on silica gel (230-400 mesh, 350 g), eluting with agradient of methanol/methylene chloride (1/90-10/90). Pooling andconcentration of those fractions with an R_(f)=0.19 by TLC(methanol/chloroform, 10/90) and trituration with methanol/diethyl ethergives the title compound, NMR (CDCl₃, 400 MHz) 7.35, 7.25, 7.13, 6.08,4.78, 4.03, 3.76, 3.69, 3.62, 2.97, 2.78, 2.56, 2.33, 2.02, 1.85 δ.

EXAMPLE 42(5S)-N-[[3-[3-Fluoro-4-(3-pyrrolidinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(5S)-N-[3-[3-fluoro-4-[1-(phenylmethyl)-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 41, 1.09 g) and 20% palladium hydroxide on carbon (545 mg) inmethanol (30 mL) is shaken on the Parr apparatus under a hydrogenatmosphere at 40 psi for 1.5 hours and at 10 psi for 18 hours. Thecatalyst is then removed by filtration through Celite, and the filtrateis concentrated under reduced pressure to give the title compound, NMR(CDCl₃, 400 MHz) 7.39, 7.24, 7.11, 6.35, 4.78, 4.04, 3.77, 3.67, 3.44,3.37, 3.18, 3.11, 2.88, 2.21, 2.02, 1.86 δ.

EXAMPLE 43(5S)-N-[[3-[3-Fluoro-4-[1-[(benzyloxy)acetyl]-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting(5S)-N-[[3-[3-fluoro-4-(3-pyrrolidinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 42) for(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, HRMS calculated for C₂₅H₂₈N₃O₅F:470.2091. Found: 470.2106.

EXAMPLE 44(5S)-N-[[3-[3-Fluoro-4-[1-(hydroxyacetyl)-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 22, and making non-criticalvariations but substituting(5S)-N-[[3-[3-fluoro-4-[1-[(benzyloxy)acetyl]-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 43) for(S)-(−)-N-[[3-[4-[1-[(benzyloxy)acetyl]-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, the title compoundis obtained, FAB-HRMS calculated for C₁₈H₂₂N₃O₅F+H: 380.1622. Found:380.1625.

EXAMPLE 45(5S)-N-[[3-[3-Fluoro-4-[1-(formyl)-3-pyrrolidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 29, and making non-criticalvariations but substituting(5S)-N-[[3-[3-fluoro-4-(3-pyrrolidinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 44) for(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, HRMS calculated for C₁₇H₂₀FN₃O₄:349.1438. Found: 349.1444.

EXAMPLE 46(5S)-3-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-pyrrolidinecarboxylicacid methyl ester

Following the general procedure of EXAMPLE 26, and making non-criticalvariations but substituting(5S)-N-[[3-[3-fluoro-4-(3-pyrrolidinyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 44) for(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, HRMS calculated for C₁₈H₂₂FN₃O₅:379.1543. Found: 379.1546.

EXAMPLE 47(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2oxo-5-oxazolidinyl]methyl]acetamide

Step 1: 3,6-Dihydro-2H-pyran-4-yl trifluoromethanesulfonic acid ester

Following the general procedure of Step 2 of EXAMPLE 20, and makingnon-critical variations but substituting tetrahydropyran-4-one for1-(1,1-dimethylethoxycarbonyl)-4-piperidone, the title compound isobtained, ¹H NMR (CDCl₃, 400 MHz) 5.82, 4.27, 3.90, 2.47 δ.

Step 2: 3-Fluoro-4-(3,6-dihydro-2H-pyran-4-yl)benzenamine

Following the general procedure of Step 3 of EXAMPLE 20, and makingnon-critical variations but substituting 3,6-dihydro-2H-pyran-4-yltrifluoromethanesulfonic acid ester (EXAMPLE 47, Step 1) for3,6-dihydro-4-[[trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, mp 86°C.-88° C.

Step 3: 3-Fluoro-4-(3,6-dihydro-2H-pyran -4-yl)benzenaminecarboxylicacid phenylmethyl ester

A mixture of 3-fluoro-4-(3,6-dihydro-2H-pyran-4-yl)benzenamine (EXAMPLE47, Step 2, 2.28 g) and sodium bicarbonate (1.98 g) in tetrahydrofuran(59 mL) is treated with benzyl chloroformate (1.85 mL), and theresulting slurry is stirred at ambient temperature for six hours. Themixture is then washed with water (50 mL), the aqueous phase isextracted with methylene chloride (50 mL), and the combined organicphase is washed with saline (25 mL), dried over anhydrous sodium sulfateand concentrated under reduced pressure. The residue is thenchromatographed on silica gel (70-230 mesh, 80 g), eluting with ethylacetate/hexane (15/85 ), and those fractions with an R_(f)=0.45 by TLC(ethyl acetate/hexane, 25/75 ) are pooled and concentrated to give thetitle compound, mp 75-76° C.

Step 4:(R)-(−)-3-[3-Fluoro-4-(3,6-dihydro-2H-pyran-4-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone

Following the general procedure of Step 3 of EXAMPLE 17, and makingnon-critical variations but substituting3-fluoro-4-(3,6-dihydro-2H-pyran-4-yl)benzenaminecarboxylic acidphenylmethyl ester (EXAMPLE 47, Step 3) for3,6-dihydro-4-[[4-[(phenylmethoxy)carbonyl]amino]phenyl]-1-(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 127-130° C.

Step 5:(R)-(−)-3-[3-Fluoro-4-(3,6-dihydro-2H-pyran-4yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone

Following the general procedure of Step 4 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[3-fluoro-4-(3,6-dihydro-2H-pyran-4-yl)phenyl]- 5hydroxymethyl-2-oxazolidinone (EXAMPLE 47, Step 4) for(R)-(−)-3,6-dihydro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylic acid phenylmethyl ester, the title compound isobtained, mp 166-169° C. (decomp.).

Step 6:(S)-(−)-(N-[[3-[4-(3,6-Dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of Step 5 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[3-fluoro-4-(3,6-dihydro-2H-pyran-4-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone(EXAMPLE 47, Step 5) for(R)-(−)-3,6-dihydro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 148-151° C.

EXAMPLE 48(S)-(−)-N-[[3-[4-[Tetrahydro-2H-pyran-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 47, 1.00 g) and 10% palladium-on-carbon (637 mg) in methanol(60 mL) is shaken on a Parr apparatus under a hydrogen atmosphere at 40psi for three hours, the catalyst is removed by filtration throughCelite and the filtrate is concentrated under reduced pressure to givethe title compound, mp 191-192° C.

EXAMPLE 49(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1: 3,6-Dihydro-2H-thiopyran-4-yl trifluoromethanesulfonic acidester

Following the general procedure of Step 2 of EXAMPLE 20, and makingnon-critical variations but substituting tetrahydrothiopyran-4-one for1-(1,1-dimethylethoxycarbonyl)-4-piperidone, the title compound isobtained, NMR (CDCl₃, 400 MHz) 6.01, 3.30, 2.86, 2.62 δ.

Step 2: 3-Fluoro-4-(3,6-dihydro-2H-thiopyran-4yl)benzenamine

Following the general procedure of Step 3 of EXAMPLE 20, and makingnon-critical variations but substituting 3,6-dihydro-2H-thiopyran-4-yltrifluoromethanesulfonic acid ester (EXAMPLE 49, Step 1) for3,6-dihydro-4-[[trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, NMR(CDCl₃, 400 MHz) 6.98, 6.40, 6.35, 5.94, 3.73, 3.31, 2.84, 2.62 δ.

Step 3: 3-Fluoro-4-(3,6-dihydro-2H-thiopyran-4yl)benzenaminecarboxylicacid phenylmethyl ester

Following the general procedure of Step 3 of EXAMPLE 47, and makingnon-critical variations but substituting3-fluoro-4-(3,6-dihydro-2H-thiopyran-4-yl)benzenamine (EXAMPLE 49, Step2) for 3-fluoro-4-(3,6-dihydro-2H-pyran-4-yl)benzenamine, the titlecompound is obtained, mp 99-101° C.

Step 4:(R)-(−)-3-[3-Fluoro-4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone

Following the general procedure of Step 3 of EXAMPLE 17, and makingnon-critical variations but substituting 3-fluoro-4-(3,6-dihydro-2H-thiopyran-4-yl)benzenaminecarboxylic acidphenylmethyl ester (EXAMPLE 49, Step 3) for3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 119-122° C.

Step5:(R)-(−)-3-[3-Fluoro-4-(3,6-dihydro-2H-thiopyran-4yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone

Following the general procedure of Step 4 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[3-fluoro-4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone(EXAMPLE 49, Step 4) for(R)-(−)-3,6-dihydro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 138-141° C.

Step 6:(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of Step 5 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[3-fluoro-4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone(EXAMPLE 49, Step 5) for(R)-(−)-3,6-dihydro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 187-189° C.

EXAMPLE 50(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran4yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide

A solution of(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 49, 300 mg) in water/acetone (25%, 17 mL) is treated withN-methylmorpholine N-oxide (301 mg) followed by osmium tetroxide (2.5 wt% in t-butanol, 0.54 mL), and the resulting mixture is stirred atambient temperature overnight. The mixture is then quenched withsaturated aqueous sodium bisulfite (10 mL) and extracted with methylenechloride (2×20 mL). The combined organic phase is washed with saline (10mL), dried over sodium sulfate and concentrated under reduced pressureto give the crude product which is then chromatographed on silica gel(70-230 mesh, 30 g), eluting with a gradient of methanol/methylenechloride (3/97-5/95). Pooling of fractions with an R_(f)=0.49 by TLC(methanol/chloroform, 10/90) and trituration with methylenechloride/diethyl ether gives the title compound, mp 181-182° C.

EXAMPLE 51(S)-(−)-N-[[3-[3-Fluoro-4-(tetrahydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide S,S-dioxide

Following the general procedure of EXAMPLE 48, and making non-criticalvariations but substituting(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S dioxide (EXAMPLE 50) for(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideand recrystallizing the product from methylene chloride/diethyl ether,the title compound is obtained, mp 199-200° C.

EXAMPLE 52(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-pyran-4-yl)phenyl]-2oxo-5-oxazolidinyl]methyl]acetamide

Step 1: 4-[4-(Hydroxy)tetrahydro-2H-pyran-4-yl]benzenaminecarboxylicacid phenylmethyl ester

Following the general procedure of Step 1 of EXAMPLE 17, and makingnon-critical variations but substituting tetrahydropyran-4-one forN-(carbobenzyloxy)-4-piperidone, the title compound is obtained, mp143-145° C.

Step 2: 4-(3,6-Dihydro-2H-pyran-4-yl)benzenaminecarboxylic acidphenylmethyl ester

Following the general procedure of Step 2 of EXAMPLE 17, and makingnon-critical variations but substituting4-[4-(hydroxy)tetrahydro-2H-pyran-4-yl]benzenaminecarboxylic acidphenylmethyl ester (EXAMPLE 52, Step 1) for4-hydroxy-4-[4[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester and recrystallizing the crude product from ethylacetate/hexane, the title compound is obtained, mp 145-148° C.

Step 3:(R)-(−)-3-[4-(3,6-Dihydro-2H-pyran-4-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone

Following the general procedure of Step 3 of EXAMPLE 17, and makingnon-critical variations but substituting4-(3,6-dihydro-2H-pyran-4-yl)benzenaminecarboxylic acid phenylmethylester (EXAMPLE 52, Step 2) for3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester and triturating the crude product with ethylacetate/hexane (50/50), the title compound is obtained, Anal. Calcd forC₁₅H₁₇NO₄: C: 65.44; H, 6.22; N, 5.09. Found: C: 65.05; H, 6.04; N,4.91.

Step 4:(R)-(−)-3-[4-(3,6-Dihydro-2H-pyran-4yl)phenyl]-5-[[(methylsulfonyl(oxymethyl]-2-oxazolidinone

Following the general procedure of Step 4 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[4-(3,6-dihydro-2H-pyran-4yl)phenyl]-5-hydroxymethyl-2-oxazolidinone(EXAMPLE 52, Step 3) for(R)-(−)-3,6-dihydro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 182-184° C.

Step 5:(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-pyran-4yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of Step 5 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[4-(3,6-dihydro-2H-pyran-4-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone(EXAMPLE 52, Step 4) for(R)-(−)-3,6-dihydro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, NMR (CDCl₃, 400MHz) 7.45, 7.36, 6.63, 6.09, 4.77, 4.31, 4.05, 3.92, 3.80, 3.65, 2.48,2.01 δ.

EXAMPLE 53(S)-(−)-N-[[3-[4-[Tetrahydro-2H-pyran-4-yl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 48, and making non-criticalvariations but substituting(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-pyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 52) for(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide, the title compound is obtained, mp 185°C.-187° C.

EXAMPLE 54(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1: 4-[4-(Hydroxy)tetrahydro-2H-thiopyran-4-yl]benzenaminecarboxylicacid phenylmethyl ester

Following the general procedure of Step 1 of EXAMPLE 17, and makingnon-critical variations but substituting tetrahydrothiopyran-4-one forN-(carbobenzyloxy)-4-piperidone and recrystallizing the product fromethyl acetate/hexane, the title compound is obtained, mp 152-154° C.

Step 2: 4-(3,6-Dihydro-2H-thiopyran-4-yl)benzenaminecarboxylic acidphenylmethyl ester

Following the general procedure of Step 2 of EXAMPLE 17, makingnon-critical variations but substituting4-[4-(hydroxy)tetrahydrothiopyran-4-yl]benzenaminecarboxylic acidphenylmethyl ester (EXAMPLE 54, Step 1) for4-hydroxy-4-[[4-[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester and triturating the crude product with diethylether or recrystallizing from ethyl acetate/hexane, the title compoundis obtained, mp 150-152° C.

Step 3:(R)-(−)-3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone

Following the general procedure of Step 3 of EXAMPLE 17, and makingnon-critical variations but substituting4-(3,6-dihydro-2H-thiopyran-4-yl)benzenaminecarboxylic acid phenylmethylester (EXAMPLE 54, Step 2) for3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1-(2H)-pyridinecarboxylicacid phenylmethyl ester and triturating the crude product withmethanol/methylene chloride, the title compound is obtained, mp 182-184°C. (decomp.).

Step 4:(R)-(−)-3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone

Following the general procedure of Step 4 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-5-hydroxymethylsulfonyl)-2-oxazolidinone(EXAMPLE 54, Step 3) for(R)-(−)-3,6-dihydro-4-[4-[5-(hydroxymethyl)2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester and triturating the crude product with methylenechloride/diethyl ether (25/75), the title compound is obtained, mp171-174° C. (decomp.).

Step 5:(S)-(−)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of Step 5 of EXAMPLE 17, and makingnon-critical variations but substituting(R)-(−)-3-[4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone(EXAMPLE 54, Step 4) for(R)-(−)-3,6-dihydro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1-(2H)-pyridinecarboxylicacid phenylmethyl ester and acetonitrile for isopropanol, the titlecompound is obtained, mp 169° C.-173° C. (decomp.).

EXAMPLE 55(S)-(−)-N-[[3-[4(3,6-Dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide

Following the general procedure of EXAMPLE 50, and making non-criticalvariations but substituting(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide EXAMPLE 54) for(S)-(−)-N-[[3-[4-3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideand triturating the product with ethyl acetate/methylene chloride, thetitle compound is obtained, mp 185-187° C.

EXAMPLE 56(S)-(−)-(N)-[[3-[4-[1-(Formyl)-3,6-dihydro-2H-pyridin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 29, and making non-criticalvariations but substituting(S)-(−)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide (EXAMPLE 38) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 148-151° C.

EXAMPLE 57(S)-(-)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid methyl ester

Following the general procedure of EXAMPLE 26, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)-3fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 38) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, NMR (CDCl₃, 400 MHz) 7.35, 7.18, 7.10,6.85, 5.89, 4.78, 4.08, 4.02, 3.78, 3.71, 3.64, 2.45, 2.00 δ.

EXAMPLE 58(S)-(-)-N-[[2-Oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)phenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:(S)-(-)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester

Following the general procedure of step 1 of EXAMPLE 38, and makingnon-critical variations but substituting(S)-(-)-N-[[3-[4-(trimethylstannyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamidefor(S)-(-)-N-[[3-[4-(trimethylstannyl)-3-fluorophenyl]2-oxo-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, NMR (CDCl₃, 400 MHz) 7.45, 7.35, 6.55,6.00, 4.77, 4.05, 3.80, 3.63, 2.49, 2.01, 1.48 δ.

Step 2:(S)-(−)-N-[[2-Oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)phenyl]-5-oxazolidinyl]methyl]acetamide

A solution of(S)-(-)-4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 58, step 1, 0.92 g) in drymethylene chloride (8.8 mL) at 0° C. under N₂ is treated withtrifluoroacetic acid (2.2 mL) over one minute, and the resulting mixtureis stirred at 0° C. for four hours and added slowly to saturated aqueouspotassium carbonate (30 mL) at 0° C. to neutralize excesstrifluoroacetic acid. The mixture is then diluted with water (50 mL) andsaline (50 mL), extracted with methanol/methylene chloride (3×150 mL,25/75), and the combined organic phase is dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the titlecompound, mp 164-166° C. (decomp.).

EXAMPLE 59(S)-(-)-N-[[2-Oxo-3-[4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 18, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 58) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)phenyl]-5-oxazolidinyl]methyl]acetamideand acetoxyacetyl chloride for benzyloxyacetyl chloride, the titlecompound is obtained, HRMS calcd for C₂₁H₂₅N₃O₆: 415.1743. Found:415.1752.

EXAMPLE 60(S)-(-)-N-[[3-[4-[-1-(Hydroxyacetyl)-3,6-dihydro-2H-pyridin-4-yl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 40, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 59) for(S)-(-)-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-3,6-dihydro-2H-pyridin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, HRMS (FAB) calcd for C₁₉H₂₃N₃O₅+H:374.1716. Found: 374.1713.

EXAMPLE 61(S)-(-)-N-[[3-[4-[1-(Formyl)-3,6-dihydro-2H-pyridin-4-yl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 29, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 58) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 149-152° C.

EXAMPLE 62(S)-(-)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]phenyl]3,6-dihydro-1(2H)-pyridinecarboxylicacid methyl ester

Following the general procedure of EXAMPLE 26, and making non-criticalvariations but substituting(S)-(-)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)phenyl]-5-oxazolidinyl]methyl]acetamideEXAMPLE 58) for(S)-(-)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 142-145° C.

EXAMPLE 63(S)-(-)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-oxo-5-oxazolidinyl]methyl]acetamideS-oxide

A solution of sodium periodate (192 mg) in water at 0° C. is treatedwith a slurry of(S)-(-)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 11, 300 mg) in methanol (10 mL), and the resulting mixture isallowed to slowly warm to ambient temperature over approximately onehour and is stirred overnight. The is then concentrated to removemethanol, diluted with water (20 mL) and extracted withmethanol/chloroform (3×30 mL, 5/95). The combined organic phase iswashed with saline (20 mL), dried over anhydrous sodium sulfate andconcentrated under reduced pressure to give the crude product which isthen chromatographed on silica gel (30 g, 70-230 mesh), eluting withmethanol/methylene chloride (5/95). Those fractions an R_(f)=0.39 BY TLC(methanol/chloroform, 10/90) were pooled and concentrated and theresidue was recrystallized from methylene chloride/diethyl ether to givethe title compound, mp 150-151° C.

EXAMPLE 64(S)-(-)-N-[[3-[4-(3,6-Dihydro-2H-thiopyran-4-yl)phenyl)-2-oxo-5-oxazolidinyl]methyl]acetamideS-oxide

Following the general procedure of EXAMPLE 63, and making non-criticalvariations but substituting(S)-(-)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-2oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 54) for(S)-(-)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 158-162° C. (decomp.).

A mixture of(S)-(-)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideS,S-dioxide (EXAMPLE 55, 75 mg) and 10% palladium-on-carbon (44 mg) intetrahydrofuran (20 mL) is stirred under a hydrogen atmosphere (balloon)for one hour, the catalyst is removed by filtration through Celite, thefiltrate is concentrated under reduced pressure and the residue isrecrystallized from methylene chloride/diethyl ether to give the titlecompound, mp 190-192° C. (decomp.).

EXAMPLE 66 3-(4-amino-2-flurophenyl)pyrrolidine

Step 1: 2-(2-fluoro)-4-nitrophenyl)-dimethylmalonate

A flame-dried 500 mL round bottom flask equipped with spinbar andadditional funnel was charged with sodium hydride (4.0 g, 0.10 mol).This oil dispersion was washed three times with pentane (30 mL), driedunder house vacuum, diluted with 50 mL of freshly distilledtetrahydrofuran, and cooled to 0° C. The grey suspension was drop-wisetreated with a 100 mL THF solution of dimethylmalonate (5.7 mL, 50 mmol)with copious gas evolution. The resulting thick suspension was treatedwith a 100 mL THF solution of 3,4-difluoronitrobenzene, quickly turninggolden in color and was warmed to 50° C. for 16 hours. At this time, thedeep red wine homogenous solution was cooled to RT, quenched with 300 mL1M hydrochloric acid, and volatiles removed in vacuo. The resultingaqueous acidic residue was extracted three time with ethyl acetate (200mL) with the combined organics washed once with brine (200 mL), driedover Mg SO₄, filtered and concentrated to give 13.58 g of a brown solid.This material was triturated with a mixture of ethylacetate/hexane/dichloromethane to afford 7.60 g of the title compound asa light yellow solid. The filtrate was concentrated and purified by Prep500 BPLC on a single silica gel cartridge eluting with 25% ethylacetate/hexane to afford and additional 3.95 g of the title compound.Total yield 10.60 g (78%), mp 108-109. mp 108-109° C.; R_(f)=0.38 (25%ethyl acetate/hexane); IR (mull) 1744, 1736, 1532, 1438, 1357, 1345,1273, 1243, 1232, 812 cm⁻¹; ¹H NMR (300 NM, CDCl₃) δ8.09 (dt, 1H J=2.2 &J=7.8 Hz, aromatic), 7.99 (ddd, 1H, J=2.3 & 9.4 Hz, aromatic), 7.74 (dd,1H, J=7.1 & J=8.6 Hz, aromatic), 5.08 (s, 1H, methane), 3.81 (s, 6H,methyls); Anal. Calcd for C₁₁H₁₀N₁O₆F₁: C, 48.74; H, 3.72; N, 5.17.Found: C, 48.74; H, 3.84; N, 5.14.

Step 2: 2-(2-fluoro-4-nitrophenyl)-2-(cyanomethyl)-dimethylmalonate

An oven-dried 100 mL round bottom flask equipped with spinbar and refluxcondenser was charged with 2-(2-fluoro-4-nitrophenyl)-dimethylmalonate(EXAMPLE 66, Step 1, 3.25 g, 12.0 mmol) and 60 mL acetone. This yellowhomogenous solution was treated with a single portion of powderedpotassium carbonate (4.98 g, 36 mmol) instantly turning red in color.This suspension was added to by bromoacetonitrile (1.3 mL, 18 mmol) andheated to reflux for 16 hours. At this time, the now brown suspensionwas cooled to RT, diluted with 100 mL 1M hydrochloric add, and extractedtwice with ethyl acetate (150 mL). The combined organics were washedonce with brine (100 mL), dried over MgSO₄, filtered, and concentratedto give 4.10 of a crude brown foam. This material was purified by Prep500 HPLC on a single silica gel cartridge eluting with 30% ethylacetate/hexane to afford 3.60 g of an off-white solid. This material wasrecrystallized from ethyl acetate/hexanes to give 3.14 g (84%) of thetitle compound as white needles. mp 137-138° C.; R_(f)=0.26 (30% ethylacetate/hexanes); IR (mull) 1749, 1730, 1527, 1355, 1290, 1276, 1262,1234, 812, 739. cm⁻¹; ¹ H NMR (300 NM, CDCl₃) 8.12 (ddd, 1H, J_(HP)=0.8,J=2.2, J=8.6 Hz, aromatic) 8.01 (dd, 1H, J=2.3 & 10.8 Hz, aromatic),7.48 (dd, 1H, J=7.6 & J=8.7 HZ, aromatic), 3.92 (s, 6H, methyls), 3.34(s, 2H, methane); ¹³C NMR (76 MHz, CDCl₃) 166.5, 169.6 (J_(CF)=263 Hz),148.7, 130.2 (J_(CF)=3 Hz), 129.9 (J_(CF)=13 Hz), 119.4 (J_(CF)=3Hz),11.9 (J_(CF)=28 Hz), 68.0, 64.1, 24.2; Anal. Calcd for C₁₃H₁₁N₂O₆F₁: C,50.33; H, 3.57; N, 9.03. Found: C, 60.23; H, 3.73; N, 9.06.

Step 3: 2-(4-amino-2-fluorophenyl)-2-carbomethoxypyrrolidinone

A 500 mL Parr flask was charged with a solution of2-(2-fluoro-4-nitrophenyl)-2-(cyanomethyl)-dimethylmalonate (EXAMPLE 66,Step 2, 1.236 g, 4.0 mmol) in 100 mL methanol and 1.17 g 10% palladiumon carbon. The black suspension was placed under 40 psi hydrogen withshaking for 64 hours. The Parr was removed from the hydrogentaor, thereaction mixture was filtered through a pad of CELITE and concentratedto afford 1.02 g of a white foam. This material was purified by LC on 70g (230-400) silica gel eluting with ethyl acetate to afford 824 mg (82%)of the compound as a white amorphous solid. R_(f)=0.20 (75% ethylacetate/hexanes); IR (mull) 3359, 3233, 1738, 1695, 1694, 1634 1515,1254, 1276, 1128, cm⁻¹; ¹H NMR (300 MHz CDCl₃) δ7.15 (t, 1H, J=9.0 Hz,aromatic), 6.58 (bs, 1H, O═C—NH), 6.41 (m, 2H, aromatic), 3.80 (bs, 2H,NH₂), 3.77 (s, 3H, CH₃), 3.49 (m, 1H, N—CH_(2a)), 3.25 (m, 2H, C—CH₂s),2.28 (m, 1H, N—CH_(2b)); ¹³C NMR (75 MHz, CDCl₃) 173.6, 170.9, 161.4(J_(CF)=245 Hz), 147.7 (J_(CF)=11 Hz), 128.9 (J_(CF)=5 Hz), 115.7(J_(CF)=14 Hz), 110.2, 102.5, (J_(CF)=25 Hz) 56.9, 53.2, 39.4, 34.3; KF.Water=0.87%; Anal. Calcd for C₁₂H₁₃N₂O₃F₁ with 0.87% water C, 56.64; H,5.25; N, 11.01. Found: C, 56.78; H, 5.34; N, 11.01. HRMS Calcd forC₁₂H₁₃N₂O₃F₁: 252.0910. Found: 252.0902.

Step 4: 2-(4-amino-2-fluroorphenyl-2-carbomethyloxypyrrolidinone

A 100 mL recovery flask containing2-(4-amino-2-fluorophenyl)-2-carbomethoxypyrrolidinone (EXAMPLE 66, Step3, 930 mg, 3.7 mmol) was charged with 26 mL DMSO and sodium cyanide (542mg, 11.1 mmol). This rose colored suspension was heated to 150° C. for30 minutes becoming reddish/brown in color with some gas evolution. Atthis time, the reaction was cooled to RT, DMSO removed under reducedpressure (approx. 60° C., 0.1 mm Hg), with the resulting residue dilutewith 30 mL brine and extracted three times with dichloromethane (30 mL).The combined organics were washed once with brine (15 mL), dried overMgSO₄, filtered and concentrated to give 521 mg of a red/brown oil. TLCindicated remaining product in the brine layers and they were combinedand extracted three times with ethyl acetate (30 mL). These combinedorganics were washed once with brine (15 mL), dried over MgSO₄,filtered,and concentrated to give an additional 230 mg of a red/brown oil. Thesecrude extracts were purified by LC on 49 g (230--400) silica gel elutingwith 5% methanol/ethyl acetate to afford 628 mg (88%) of the titlecompound as a light yellow solid. mp 157-160° C.; R_(f)=0.24 (ethylacetate); IR (mull) 3465, 3363, 1680, 1630, 1614, 1515, 1447, 1285, 830,828 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ7.73 (bs, 1H, O═C—NH), 6.85 (t, 1H,J=8.4 Hz, aromatic), 6.31 (m, 2H, aromatic), 5.28 (bs, 2H, NH₂), 3.48(t, 1H, J=9.4 Hz, Ph—CH), 3.24 (m, 2H, C—CH₂s), 2.35 (m, 1H, N-CH_(2a)),1.95 (m, 1H, N—CH_(2b)); ¹³C NMR (75 MHz, CDCl₃) 178.8, 161.9(J_(CF)×244 HZ), 147.5 (J_(CF)=11 Hz), 130.4 (J_(CF)=6 Hz), 115.7(J_(CF)=15 Hz), 111.1 (J_(CF)=2 Hz), 102.3 (J_(CF)=25 Hz), 41.5, 40.5,30.1; HRMS Calcd for C₁₀H₁₁N₂O₁F₁+H: 195.0134. Found: 195.0937.

Step 5: 3-(4-amino-2-fluorophenyl)pyrrolidine

100 mL round bottom flask equipped with spinbar and reflux condenser wascharged with 2-(4-amino-2-fluorophenyl)-2-carbomethoxypyrrolidinone(EXAMPLE 66, Step 4, 430 mg, 2.2 mmol) and 22 mL freshly distilled THFfollowed by cooling to 0° C. This light yellow homogeneous solution wastreated with a 1M solution of lithium aliminumhydride (11 mL, 11 mmol)instantly becoming an opaque light rose color with copious gasevolution. The reaction was warmed to RT then heated to reflux with theformation of a gelatanous precipitate. After 20 hours, the nowgreen/yellow truck suspension was successively quenched by the additionof 0.42 mL water, 0.38 mL 5N sodium hydroxide, and 1.5 mL water. Theresulting thick gelatinous suspension was diluted with ethyl acetate,filtered through a pad of Celite, and concentrated to give 392 mg of ayellow oil. This material was purified by LC on 25 g (230-400) silicagel eluting with 2:17:81 sat. NH₄OH:methanol:dichloromethane to afford295 mg (74%) of the title compound as a light yellow oil. This materialwas dissolved in a mixture of methanol/ethylacetate and treated withgaseous HCl with observable change. This solution was concentrated toafford a peach colored foam that failed to recrystallize from manydifferent solvent combinations. R_(f)=0.20 (2:17:8) satNH₄OH:methanol:dichloromethane); IR (mull) 3139, 3042, 3016, 2766, 2562,1514, 1485, 1444, 1266, 1108 cm⁻¹; ¹H NMR (300 MHz, CDCl₃) δ6.99 (t, 1H,J=8.2 Hz, aromatic), 6.39 (m, 2H, aromatic), 3.70 (bs, 2H, Ph—NH₂s),3.27 (m, 2H, methane, N-CH _(2a)—CH), 3.11 (m, 2H, N-CH ₂s—CH2), 2.80(dd, 1H, J=6.2 & 8.9 Hz, N—CH _(2b)—CH), 2.3 (bs, 1H, NH), 2.14 (m, 1H,N—CH₂—CH _(2a)), 1.81 (m, 1H, N—CH₂—CH_(2b)); ¹³C NMR (75 MHz, CDCl₃)161.4 (J_(CF)=243 Hz), 146.0 (J_(CF)=11 Hz), 128.4 (J_(CF)=7 HZ), 119.9(J_(CF)=152 HZ), 110.5 (J_(CF)=2 HZ), 102.1 (J_(CF)=26 HZ), 53.6, 47.0,38.1, 32.9; Anal. Calcd for C₁₀H₁₃N₂F₁: C, 47.45; H, 5.93; N, 11.07.Found: C, 47.10; H, 6.10; N, 10.74. HRMS Calcd for C₁₀H₁₃N₂F₁: 180.1063.Found: 180.1060.

EXAMPLE 67(S)-(-)-N-[[3-[3-Fluoro-4-(dihydrothien-3-yl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1:3-Fluoro-4-[3-(hydroxy)tetrahydrothiophen-3-yl]-benzenaminecarboxylicacid phenylmethyl ester

A solution of1-(3-fluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane(EXAMPLE 20, Step 1, 1.00 g) in dry tetrahydrofuran (16 mL) at −78° C.under N₂ is treated with see-butyllthium (1.3 M in cyclohexane, 3.30 mL)dropwise over 2 mins, and the resulting mixture is stirred at −78° C.for 2 hrs. The mixture is then treated with a solution oftetrahydrothiophen-3-one (423 mg) in dry tetrahydrofuran (4.1 mL)dropwise over 2 mins and is stirred at −78° C., allowing the coolingbath to expire over 4 hrs. The mixture is then quenched with saturatedaqueous ammonium chloride (25 mL), diluted with water (25 mL), thelayers are separated, and the combined organic phase is washed withsaline (20 mL), dried over anhydrous sodium sulfate and concentratedunder reduced pressure. The residue is dissolved in methanol (16 mL) andtreated with anhydrous potassium carbonate (1.09 g), and the mixture isstirred at ambient temperature for 30 mins, concentrated under reducedpressure, diluted with water (20 mL) and extracted with diethyl ether(2×20 mL). The combined organic phase is washed with saline (10 mL),dried over anhydrous magnesium sulfate and concentrated under reducedpressure to give the crude3-fluoro-4-[3-(hydroxy)tetrahydrothiophen-3-yl]benzenamine intermediate(R_(f)=0.37 by TLC, ethyl acetate/hexane (50/50)). A solution of thisintermediate in tetrahydrofuran (16 mL) and water (8 mL) is then treatedwith sodium bicarbonate (662 mg) and benzyl chloroformate (0.56 mL), andthe resulting mixture is stirred at ambient temperature for 4 hrs,diluted with water (8 mL), the layers are separated, and the organicphase is washed with saline (10 mL), dried over anhydrous magnesiumsulfate and concentrated under reduced pressure. The residue ischromatographed on silica gel (230-400 mesh, 150 g), eluting with ethylacetate/hexane (25/75), and those fractions with an R_(f)=0.19 by TLC(ethyl acetate/hexane, 25/75) are pooled and concentrated to give thetitle compound, mp 134-135° C.

Step 2: 3-Fluoro-4-(dihydrothien-3-yl)benzenaminecarboxylic acidphenylmethl ester

Following the general procedure of EXAMPLE 17, Step 2, and makingnon-critical variations but substituting3-fluoro-4-[3-(hydroxy)tetrahydrothiophen-3yl]benzenaminecarboxylic acidphenylmethyl ester (EXAMPLE 67, Step 1) for4-hydroxy-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester, the title compound is obtained as a mixture ofthe 2,5- and 4,5-dihydro regioisomers. NMR (CDCl₃, 400 MHz) 7.40, 7.21,7.141 7.02, 6.73, 6.69, 6.31, 5.21, 4.10, 3.94, 3.33 and 3.15 δ.

Step 3:(R)-3-[3-Fluoro-4-(dihydrothien-3-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone

Following the general procedure of EXAMPLE 17, Step 3, and makingnon-critical variations but substituting3-fluoro-4-(dihydrothien-3-yl)benzenaminecarboxylic acid phenylmethylester (EXAMPLE 67, Step 2, mixture of the 2,5- and 4,5-dihydroregioisomers) for3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained as a mixture ofthe 2,5- and 4,6-dihydro regioisomers. HRMS calculated forC₁₄H₁₄N₁F₁O₃S₁: 295.0678. Found: 295.0676.

Step 4:(R)-3-[3-Fluoro-4-(dihydrothien-3-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone

Following the general procedure of EXAMPLE, 17, Step 4, and makingnon-critical variations but substituting(R)-3-[3-fluoro-4-(dihydrothien-3-yl)phenyl]-5-hydroxymethyl-2-oxazolidinone(EXAMPLE 67, Step 3, mixture of the 2,5- and 4,5-dihydro regioisomers)for(R)-(-)-3,6-dihydro-4-[4-[5-(hydroxymethyl)2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained as a mixture ofthe 2,5- and 4,5-dihydro regioisomers. HRMS calculated forCH₁₅NH₁₆N₁F₁O₅S₂: 373.0454. Found: 373.0440.

Step 5:(S)-N-[[3-[3-Fluoro-4-(dihydrothien-3yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 17, Step 5, and makingnon-critical variations but substituting(R)-3-[3-fluoro-4-(dihydrothien-3-yl)phenyl]-5-[[(methylsulfonyl)oxy]methyl]-2-oxazolidinone(EXAMPLE 67, Step 4, mixture of the 2,5- and 4,5-dihydro regioisomers)for(R)-(-)-3,6-dihydro-4-[4-[5[-[]methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained as a mixture ofthe 2,5- and 4,5-dihydro regioisomers. Anal. calculated forC₁₆H₁₇F₁N₂O₃S₁, C, 57.13; H, 5.09; N, 8.33. Found: C, 56.89; H, 5.18; N,8.24.

EXAMPLE 68(5S)-N-[[3-[3-Fluoro-4-(2,5-dihydro-1-oxido-3-thienyl-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetmaide(68a) and(5S)-N-[[3-[3-Fluoro-(4,5-dihydro-1-oxido-3-thienyl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(68b)

Following the general procedure of EXAMPLE 63, and making non-criticalvariations but substituting(S)-N-[[3-[3-fluoro-4-(dihydrothien-3-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 67, Step 5, mixture of the 2,5- and 4,5-dihydro regioisomers)for(S)-(-)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideand separating the regioisomers by chromatography on silica gel (230-400mesh, methanol/methylene chloride (4/96) eluent), the title compoundsare obtained. mp (68a) 208-210° C. (decomp.); NMR (68b) (CDCl₃, 400 MHz)7.55, 7.46, 7.27, 7.13, 6.11, 4.82, 4.07, 3.82-3.62, 3.43, 3.23, 3.20and 2.03 δ.

EXAMPLE 69(S)-N-[[3-[3-Fluoro-4-(2,5-dihydro-1,1-dioxido-3-thienyl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(69a) and(S)-N-[[3-[3-Fluoro-4-(4,5-dihydro-1,1-dioxido-3-thienyl)-phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(69b)

Following the general procedure of EXAMPLE 50, and making non-criticalvariations but substituting(S)-N-[[3-[3-fluoro-4-(dihydrothien-3-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 67, Step 5, mixture of the 2,5- and 4,5-dihydro regioisomers)for(S)-(-)-N-[[3-[4-(3,6-dihydro-2H-thiopyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideand separating the regioisomers by HPLC (Chiralpak AD, 10%isopropanol/methanol (0.05% diethylamine), 0.5 mL,/min), the titlecompounds are obtained. mp (69a) 183-185° C. (decomp); (69b) 238-239° C.(decomp.).

EXAMPLE 70(S)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-5,6-dihydro-2H-pyridin-3-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:5,6-Dihydro-3-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester

Following the general procedure of EXAMPLE 20, Step 2, and makingnon-critical variations but substituting1-(1,1-dimethylethoxycarbonyl)-3-piperidone for1-(1,1-dimethylethoxycarbonyl)-4-piperidone and isolating the desiredregioisomer by chromatography on silica gel (70-230 mesh, ethylacetate/hexane (10/90) eluent), the title compound is obtained, NMR(CDCl₃, 400 MHz) 5.92, 4.04, 3.49, 2.30 and 1.47 δ.

Step 2:(S)-3-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-5,6-dihydro-1(2H)-pyridine-1-carboxylicacid 1,1-dimethylethyl ester

Following the general procedure of EXAMPLE 38, Step 1, and makingnon-critical variations but substituting5,6-dihydro-3-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 70, Step 1) for3,6-dihydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, NMR(CDCl₃, 400 MHz) 7.41, 7.25, 7.17, 6.06, 4.79, 4.19, 4.06, 3.78,3.75-3.59, 3.57, 2.32, 2.03 and 1.49 δ.

Step 3:(S)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-5,6-dihydro-2H-pyridin-3-yl]-phenyl]-5-oxazolidinyl]methyl]acetamide

A solution of(S)-3-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-5,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 70, Step 2, 158 mg) in dryacetonitrile under N₂ is treated with iodotrimethylsilane (62 μL)dropwise, and the resulting solution is stirred at ambient temperaturefor 50 mins, during which additional iodotrimethylsflane (25 μL) isadded. The reaction is then treated with methanol (59 μL), stirred for 5mins and concentrated under reduced pressure to give the deprotectedintermediate. A mixture of this intermediate and triethylamine (0.122mL) in dry methylene chloride (3.6 mL) at 0° C. under N₂ is treated withacetoxyacetyl chloride (47 μL), and the resulting mixture is stirred at0° C. for 2 hrs and at ambient temperature for 2 hrs and then dilutedwith methylene chloride (20 mL), washed with water (10 mL), saturatedaqueous sodium bicarbonate (10 mL) and saline (10 mL), dried overanhydrous sodium sulfate and concentrated under reduced pressure. Theresidue is chromatographed on silica gel (70-230 mesh, 15 g), elutingwith methanol/methylene chloride (5/95), and those fractions with anR_(f)=0.5 by TLC (methanol/chloroform, 10/90) are pooled andconcentrated to give the title compound, HRMS calculated forC₂₁H₂₄N₃F₁O₆+H₁: 434.1727. Found: 434.1741.

EXAMPLE 71(S)-N-[[3-[4-[1-(Hydroxyacetyl)-5,6-dihydro-2H-pyridin-3-yl]-3-flurorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-5,6-dihydro-2H-pyridin-3-yl]phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 70, Step 3, 105 mg) and anhydrous potassium carbonate (67 mg)in methanol (4.8 mL) is stirred under N₂ at ambient temperature for 2hrs and is then neutralized with hydrochloric acid (1 M), diluted withwater (10 mL) and methylene chloride (40 mL), and the layers areseparated. The organic phase is washed with saline (10 mL), dried overanhydrous sodium sulfate and concentrated under reduced pressure to givethe crude product, which is then chromatographed on silica gel (70-230mesh, 15 g), eluting with methanol/methylene chloride (5/95). Poolingand concentration of those fractions with an R_(f)=0.30 by TLC(methanol/choroform, 10/90) gives the title compound, mp 188-190° C.

EXAMPLE 72(S)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetyl]3,4-dihydro-2H-pyridin-5-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:3-Hydroxy-3[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester

Following the general procedure of EXAMPLE 67, Step 1, and makingnon-critical variations but substituting n-(carbobenzyloxy)-3-piperidonefor tetrahydrothiophen-3-one, the title compound is obtained, mp 137—139° C.

Step 2:3,4-Dihydro-5-[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester

Following the general procedure of EXAMPLE 17, Step 2, and makingnon-critical variations but substituting3-hydroxy-3-[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 72, Step 1) for4-hydroxy-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester, the title compound is obtained, mp 138—139° C.

Step 3:(R)3,4-Dihydro-5-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester

Following the general procedure of EXAMPLE 17, Step 3, and makingnon-critical variations but substituting3,4-Dihydro-5-[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester (EXAMPLE 72, Step 2) for3,6-dihydro-4-[4-[[(phenylmethoxy)carbonyl]amino]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, HRMS calculatedfor C₂₃H₂₃N₂F₁O₅: 426.1591. Found: 426.1594.

Step 4:(R)-3,4-Dihydro-5-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-(2H)-pyridinecarboxylicacid phenylmethyl ester

Following the general procedure of EXAMPLE 17, Step 4, and makingnon-critical variations but substituting(R)-3,4-Dihydro-5-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester (EXAMPLE 72, Step 3) for(R)-(−)-pyridinecarboxylic acid phenylmethyl ester, the title compoundis obtained, NMR (CDCl₃, 400 MHz) 7.39, 7.27, 7.18, 5.23, 4.93, 4.47,4.15, 3.95, 3.71, 3.11, 2.44 and 1.97 δ.

Step 5:(S)-(−)-5-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,4-dihydro-1(2H)-pyridinecarboxylicacid phenylmethyl ester

Following the general procedure of EXAMPLE 17, Step 5, and makingnon-critical variations but substituting(R)-3,4Dihydro-5-[4-[5-[[(methylsulfonyl)oxy]phenylmethyl ester (EXAMPLE72, Step 4) for(R)-(−)-3,6dihydro-4-[4-5-[[(methylsulfonyl)oxy]oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]-1(2H)-pyridinecarboxylicacid phenylmethyl ester, the title compound is obtained, HRMS calculatedfor C₂₅H₂₆F₁N₃O₅: 467.1856. Found: 467.1862.

Step 6:(S)-N-[[2Oxo-3-[3-fluoro-4[1-[(acetoxy)acetyl]-3,4-dihydro-2H-pyridin-5-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 70, Step 3, and makingnon-critical variations but substituting(S)-(−)-5-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,4dihydro-1(2H)-pyridinecarboxylicacid phenylmethyl ester (EXAMPLE 72, Step 5) for(S)-(−)-5-[4-[5(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-3,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, mp146—148° C.

EXAMPLE 73(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-3,4-dihydro-2H-pyridin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-3,4-dihydro-2H-pyridin-5-yl]phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 72, Step 6, 238 mg) and anhydrous potassium carbonate (151 mg)in methanol (27 mL) is stirred under N₂ at ambient temperature for 2 hrsand is then neutralized with hydrochloric acid (1 M) and concentratedunder reduced pressure. The residue is then diluted with methylenechloride (100 mL) and saline (50 mL) and the resultant insoluble productis removed by filtration and dried under reduced pressure. The layers inthe filtrate are separated and the organic phase is dried over anhydroussodium sulfate and concentrated under reduced pressure to giveadditional quantities of the title compound, mp 171—173° C.

EXAMPLE 74(S)-(−)-N-[[3-[4-[1-Formyl-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1:4-Hydroxy-4-[2-fluoro-4[[(phenylmethoxy)carbonyl]amino]phenyl]-1-piperidinecarboxylicacid phenylmethyl ester

A solution of1-(3-fluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacylopentane(EXAMPLE 20, Step 1, 1.00 g) in dry tetrahydrofuran (9.8 mL) at −78° C.under N₂ is treated with sec-butyllithium (1.3 M in cyclohexane, 3.64mL) dropwise over 3 mins, and the resulting is stirred at −78° C. for 2hrs. The mixture is then treated with a solution onN-(carbobenzyloxy)-4-piperidone (919 mg) in dry tetrahydrofuran (3.9 mL)dropwise over 2 mins and is stirred at −78° C. for 2 hrs. The mixture isthen warmed to −20° C. over 1 hr and quenched with saturated aqueousammonium chloride (5 mL), diluted with water (20 mL), the layers areseparated, the aqueous phase is extracted with diethyl ether (20 mL),and the combined organic phase is washed with saline (10 mL), dried overanhydrous sodium sulfate and concentrated under reduced pressure. Theresidue is dissolved in methanol (15 mL) and treated with anhydrouspotassium carbonate (544 mg, 3.94 mmol), and the mixture is stirred atambient temperature for 30 mins, concentrated under reduced pressure,diluted with diethyl ether (30 mL), washed with water (20 mL) and saline(10 mL), dried over anhydrous magnesium sulfate and concentrated underreduced pressure to give the crude 4-(hydroxy)piperidinyl benzenamineintermediate (R_(f)=0.25 by TLC, ethyl acetate/hexane (50/50)). Amixture of this intermediate and N,N-dimethylaniline (1.00 mL) intetrahydrofuran (20 mL) is cooled to −20° C. and treated with benzylchloroformate (0.59 mL), and the resulting mixture is stirred at −20° C.for 1 hr. The mixture is then diluted with saturate aqueous potassiumcarbonate (5 mL), water (25 mL) and diethyl ether (25 mL), the layersare separated, and the organic phase is washed with water (20 mL) andsaline (20 mL), dried over anyhdrous sodium sulfate and concentratedunder reduced pressure. The residue is chromatographed on silica gel(230-400 mesh, 150 g), eluting with a gradient of ethyl acetate/hexane(25/75-50/50), and those fractions with an R _(f)=0.47 by TLC (ethylacetate/hexane, 50/50) are pooled and concentrate to give the titlecompound, NMR (400 MHz, CDCl₃) 7.35, 7.00, 6.92, 5.20, 5.16, 4.10 3.32,2.15 and 1.79 δ and Anal. calculated for C₂₇H₂₇FN₂O₅: C, 67.77; H, 5.69;N, 5.85. Found: C, 67.44; H, 5.83; N, 5.65.

Step 2:4-Fluoro-4-[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester

To a solution of diethylaminosulfur trifluoride (DAST, 0.65 mL) in drymethylene chloride (49 mL) at −78° C. under N₂ is added a solution of4-hydroxy-4-[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 74, Step 1, 2.25 g) in dry methylenechloride (47 mL) over 2 mins. The resulting mixture is stirred at −78°C. for 1 hr and at ambient temperature for 30 mins and is then adjustedto ph 8 with saturated aqueous sodium bicarbonate (50 mL), diluted withwater (50 mL), and the layers are separated. The organic phase is washedwith water (25 mL) and saline (25 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure, and the residue ischromatographed on silica gel (230-400 mesh, 150 g) eluting withmethanol/methylene chloride (0.5/99.5). Those fractions with an R₇=0.27by TLC (ethyl acetate/hexane, 25/75) are pooled and concentrated to givethe title compound (contaminated with approx. 15% of the eliminationside product). An analytical sample is prepared by radial chromatography(100 μ silica gel rotor, ethyl acetate/hexane (20/80) eluent), mp116-118° C.

Step 3:(R)-(4-Fluoro-4-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester

A solution of4-fluoro-4-[4-[[(phenylmethoxy)carbonyl]amino]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 74, Step 2, 2.03 g, contaminated withthe elimination side product) in dry tetrahydrofuran (21 mL) at −78° C.under N₂ is treated with n-butyllithium (2.80 mL, 1.6 M in hexanes)dropwise over 5 mins. The resulting mixture is stirred at −78° C. for1.25 hrs and is then treated with (R)-(−)-glycidyl butyrate (0.63 mL)dropwise. The resulting solution is stirred at −78° C. for 1 hr, warmedto ambient temperature and stirred for an additional 20 hrs, after whichthe reaction is quenched with saturated aqueous ammonium chloride (10mL), diluted with water (10 mL), dried over anhydrous magnesium sulfateand concentrated under reduced pressure to give the crude product whichis chromatographed on silica gel (230-400 mesh, 250 g), eluting withmethanol/methylene chloride (3/97). Pooling and concentration of thosefractions with an R_(f)=0.51 by TLC (methanol/chloroform, 10/90) andrepurification by silica gel chromatography (230-400 mesh, 100 g,methanol/methylene chloride (4/96) eluent) gives the title compound(contaminated with the elimination side product from the startingmaterial). An analytical sample is prepared by radial chromatography(2000μ silica gel rotor, ethyl acetate/hexane (60/40) eluent), NMR (400MHx, CDCl₃) 7.45, 7.34, 7.18, 5.16, 4.74, 4.17, 3.97, 3.72, 3.22, 2.25and 1.90  and HRMS calculated for C₂₃H₂₄F₂N₂O₅: 446.1653. Found:446.1660.

Step 4:(R)-4-Fluoro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester

A solution of(R)-4-fluoro-[4-[5-(hydroxymethyl)-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 74, Step 3, 0.17 g) and triethylamine(0.080 mL) in dry methylene chloride (2 mL) at 0° C. under N₂ is treatedwith methanesulfonyl chloride (0.031 mL) dropwise. The resulting mixtureis stirred at 0° C. for 12 hrs and at ambient temperature for 1.5 hrs,diluted with methylene chloride (10 mL), washed with water (5 mL),saturated aqueous sodium bicarbonate (5 mL) and saline (5 mL), driedover anhydrous sodium sulfate and concentrated under reduced pressure togive the title compound, HRMS calculated for C₂₄H₂₆F₂N₂O₇S+H₁: 525.1507.Found: 525.1522.

Step 5:(S)-N-[[2-Oxo-3-[4-(4-fluoro-4piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide

A mixture of(R)-4-fluoro-4-[4-[5-[[(methylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-1-piperidinecarboxylicacid phenylmethyl ester (EXAMPLE 74, Step 4, 0.190 g) and concentratedaqueous ammonium hydroxide (2 mL) in isopropanol (1 mL) and acetonitrile(2 mL) is placed in a sealed tube and immersed in an oil bath maintainedat 95° C. for 18 hrs. The mixture is then diluted with methylenechloride (20 mL), washed with water (10 mL) and saline (10 mL), driedover anhydrous sodium sulfate and concentrated under reduced pressure togive the crude 5-aminomethyl-2-oxazolidinone intermediate (R_(f)=0.13 byTLC, methanol/chloroform, 5/95). A solution of this intermediate andpyridine (0.088 mL) in dry methylene chloride (3.6 mL) under N₂ istreated with acetic anhydride (0.051 mL), and the resulting solution isstirred at ambient temperature for 18 hrs. The mixture is then dilutedwith methylene chloride (10 mL), washed with water (5 mL), saturatedaqueous sodium bicarbonate (5 mL) and saline (5 mL), dried overanhydrous sodium sulfate and concentrated under reduced pressure to givethe crude acetamide intermediate which, after being combined withapprox. 1.5 g of crude product from previous reaction workups, ischromatographed on silica gel (230-400 mesh, 150 g), eluting with agradient of methanol/methylene chloride (1/9/90-1/4/95), and thosefractions having an R_(f)=0.19 by TLC(triethylamine/methanol/chloroform, 1/9/90) are pooled and concentratedto give the title compound, mp 163-165° C.

Step 6:(S)-(−)-N-[[3-[4-[1-Formyl-4-fluoro-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-3-N-[[2-oxo-3-[4-(4-fluoro-4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 74, Step 5, 205 mg),1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (145 mg) andformic acid (28 μL) in dry tetrahydrofuran (11.6 mL) is diluted withwater to solubilize all reactants and stirred at ambient temperature for6 hrs. The reaction is then diluted with methylene chloride (30 mL),washed with water (20 mL) and saline (20 mL), dried over anhydroussodium sulfate and concentrated under reduced pressure, and the residueis chromatographed on silica gel (230-400 mesh, 40 g), eluting with agradient of methanol/methylene chloride (3/97-5/95). Those fractionswith an R_(f)=0.40 by TLC (methanol/chloroform, 10/90) are pooled andconcentrated and the residue is recrystallized from chloroform/diethylether to give the title compound, mp 180-181° C. (decomp.).

EXAMPLE 75(S)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,4,7-tetrahydro-1H-azepin-5yl]phenyl]-5oxazolidinyl]methyl]acetamide

Step 1:(2,3,4,7-Tetrahydro-5[[(trifluoromethyl)sulfonyl]oxy]-1H-azepine-1-carboxylicacid 1,1-dimethylethyl ester (a) and2,3,6,7-Tetrahydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1H-azepine-1-carboxylicacid 1,1-dimethylethyl ester (b)

Following the general procedure of EXAMPLE 20, Step 2, and makingnon-critical variations but substituting1-(1,1-dimethylethoxycarbonyl)-1,2,3,5,6,7-hexahydroazepin-4-one for1-(1,1-dimethylethoxycarbonyl)-4-piperidone and isolating theregioisomers by chromatography on silica gel (230-400 mesh, ethylacetate/hexane (5/95) eluent), the title compounds are obtained, (a) NMR(CDCl₃, 400 MHx) 5.87, 3.95, 3.55, 2.57, 1.95 and 1.46 δ and (b) NMR(CDCl₃, 400 MHz) 5.90, 3.54, 2.69, 2.35 and 1.47 δ.

Step 2:(S)-5-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-2,3,4,7-tetrahydro-1H-azepinecarboxylicacid 1,1-dimethylethyl ester

Following the general procedure of EXAMPLE 38, Step 1, and makingnon-critical variations but substituting2,3,4,7-tetrahydro-5-[[(trifluoromethyl)sulfonyl]oxy]-1(1H)-azepinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 75, Step 1(A)) for3,6-dihydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, NMR(CDCl₃, 400 MHz) 7.31, 7.12-6.95, 5.84, 4.76, 4.00, 3.98, 3.76, 3.61,3.58, 2.51, 1.97, 1.85 and 1.42 δ.

Step 3:(S)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,4,7-tetrahydro-1H-azepin-5-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 70, Step 3, and makingnon-critical variations but substituting(S)-5-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-2,3,4,7-tetrahydro-1H-azepine-1-carboxylicacid 1,1-dimethylethyl ester (EXAMPLE 75, Step 2) for(S)-(−)-3-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-5,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, HRMScalculated for C₂₂H₂₆F₁N₃O₆: 448.1884. Found: 448.1888.

EXAMPLE 76(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-2,3,4,7-tetrahydro-1H-azepin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 71, and making non-criticalvariations but substituting(S)-N-[[2-oxo-3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,4,7-tetrahydro-1H-azepin-5yl]phenyl]-5-oxazolidinyl]methylacetamide (EXAMPLE 75, Step 3) for(S)-(−)-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-5,6-dihydro-2H-pyridin-3-yl]phenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, NMR (CDCl₃, 400 MHz, mixture ofrotamers) 7.41, 7.09-7.18, 6.07, 6.00, 5.87, 4.79, 4.25, 4.21, 4.05,3.92, 3.87, 3.78, 3.67, 3.51, 2.63, 2.03 and 1.97 δ and HRMS calculatedfor C₂₀H₂₄F₁N₃O₅: 405.1700. Found: 405.1694.

EXAMPLE 77(S)-(−)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,6,7-tetrahydro-1H-azepin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide

Step 1:(S)-4-[4-[5-[(Acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-2,3,6,7-tetrahydro-1H-azepine-1-carboxylicacid 1,1-dimethylethyl ester

Following the general procedure of EXAMPLE 38, Step 1, and makingnon-critical variations but substituting2,3,6,7-tetrahydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1(1H)-azepinecarboxylicacid 1,1-dimethylethyl ester (EXAMPLE 75, Step 1(B)) for3,6-dihydro-4-[[(trifluoromethyl)sulfonyl]oxy]-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, mp164-165° C.

Step 2:(S)-(−)-N-[[2-Oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,6,7-tetrahydro-1H-azepin-4-yl]phenyl]-5oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 70, Step 3, and makingnon-critical variations but substituting(S)-4-[4-[5-[(acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-2,3,6,7-tetrahydro-1H-azepine-1-carboxylicacid 1,1-dimethylethyl ester (EXAMPLE 77, Step 1) for(S)-(−)-3-[4-[5-[acetylamino)methyl]-2-oxo-3-oxazolidinyl]-2-fluorophenyl]-5,6-dihydro-1(2H)-pyridinecarboxylicacid 1,1-dimethylethyl ester, the title compound is obtained, NMR(CDCl₃, 400 MHz, mixture of rotamers) 7.39, 7.15, 6.22, 5.90, 4.79,4.04, 3.80-3.50, 2.70, 2.50, 2.19 and 2.02 δ and Anal. calculated forC₂₂H₂₆F₁N₃O₆: C, 59.05; H, 5.86: N, 9.39. Found. C, 58.70; H, 5.80; N,9.43.

EXAMPLE 78(S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)-2,3,6,7-tetrahydro-1H-azepin-4-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 71, and making non-criticalvariations but substituting(S)-(−)-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-2,3,6,7-tetrahydro-1H-azepin-4-yl]phenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 77, Step 2) for(S)-(−)-N-[[2-oxo-3-[3-fluoro-4-[1-[(acetoxy)acetyl]-5,6-dihydro-2H-pyridin-3-yl]phenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, NMR (CDCl₃, 400 MHz, mixture ofrotamers) 7.41, 7.13, 6.08, 5.90, 4.78, 4.22, 4.04, 3.85-3.59,3.51-3.41, 2.70, 2.52 and 2.02 δ and Anal. calculated for C₂₀H₂₄F₁N₃O₅:C, 59.25; H, 5.97; N, 10.36. Found. C, 58.91; H, 6.04; N, 10.19.

EXAMPLE 79(5S)-(−)-N-[[3-[4-[1-(Hydroxyacetyl)hexahydro-1H-azepin-4-yl]-3-fluorophenyl]-2oxo-5-oxazolidinyl]methyl]acetamide(as a mixture of diastereomers)

Following the general procedure of EXAMPLE 48, and making non-criticalvariations but substituting(S)-(−)-N-[[3[4-[1-(hydroxyacetyl)-2,3,4,7-tetrahydro-1H-azepin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(EXAMPLE 76, Step 3, for(S)-(−)-N-[[3-[4-(3,6-dihydro-2H-pyran-4-yl)-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamideand purifying the product by chromatography on silica gel (70-230 mesh,methanol/methylene chloride (7.5/92.5) eluent), the title compound isobtained, HRMS calculated for C₂₀H₂₆F₁N₃O₅+H₁: 408.1935. Found:408.1928.

EXAMPLE 80(S)-N-[[3-[3-Fluoro-4-(3,4-dihydro-2H-pyran-6-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1: 6-(tributylstannyl)-3,4-dihydro-2H-dihydropyran

A solution of 3,4-dihydro-2H-dihydropyran (2.000 g, 23.8 mmol) andN,N,N′,N′-tetramethylethylenediamine (0.50 mL, 3.09 mmol) under anitrogen atmosphere was cooled to 0° C. and treated with n-butyllithium(19.30 mL of a 1.6 M solution in hexane, 30.94 mmol). The mixture wasthen warmed to ambient temperature overnight. The resultant mixture wascooled to −78° C., dry tetrahydrofuran (20 mL) was added, and thentributyltin chloride (6.40 mL, 23.8 mmol). The mixture was stirred at−78° C. for 1 h and then warmed to ambient temperature for 2 h. Thereaction mixture was diluted with diethyl ether (50 mL), transferred toa separatory funnel and washed with 5% aqueous ammonnium hydroxide andbrine. The organic layer was then dried, filtered and concentrated togive a crude product. Distillation of the residue under reduced pressureafforded 1.80 g (47%) of the title compound with a purity of 55%.

Step 2:(S)-N-[[3-[3-Fluoro-4-(3,4-dihydro-2H-pyran-6-yl)phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A solution of(S)-N-[[3-[3-fluoro-4-iodophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(0.200 g, 0.53 mmol) in 1-methyl-2-pyrrolidinone (5mL) under a nitrogenatmosphere was treated with Pd₂dba_(s) (0.018 g, 0.01 mmol) andtri(2-furyl)phosphine (0.009 g, 0.04 mmol). After stirring 10 min atambient temperature, the mixture was treated with6-(tributylstannyl)-3,4-dihydro-2H-dihydropyran (0.538 g, 55% purity,0.80 mmol). The atmosphere was evacuated and filled with nitrogen threetimes and then the mixture heated to 90° C. for 24 h. At this time thereaction mixture was cooled to ambient temperature and poured into ethylacetate. A precipitate was noticed and removed by filtering the mixturethrough Celite. The filtrate was transferred to a separatory funnel andwashed with water and brine, dried over sodium sulfate, filtered andconcentrated in vacuo. The reside was chromatographed over silica gel,eluting with hexane, 20% acetone/hexane, and finally 5%methanol/dichloromethane. Appropriate fractions were combined andconcentrated in vacuo to give 0.196 g of a material containing a smallamount of 1-methyl-2-pyrrolidinone. Recrystallization provided 0.128 g(68%) of the title compound. mp 161-163° C.; MS(EI): m/z 334.

EXAMPLE 81(S)-N-[[3-[3-Fluoro-4[1-(carbobenzyloxy)-3-azetidinyl]-phenyl]-2-oxo-5-oxazolidinyl]methyl]-acetamide

Step 1:3-(4-Amino-2-fluorophenyl)-3-hydroxy-1-(1,1-diphenylmethyl)azetidine

Sec. butyllithium (22.5 mL) of a 1.3M solution in cyclohexane, 29.5mmol) was added dropwise to a stirred solution of1-(3-fluorophenyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane(Example 20, Step 1) (6.0 g, 23.7 mmol) at −78° C. under nitrogen in dryTHF (75 mL). After 2 hr a solution of1-(1,1-diphenylmethyl)azetidine-3one (5.6 g, 23.6 mmol) in dry THF (60mL) was added dropwise and stirring continued at −78° for 2 hr, when thecooling bath was removed. After reaching room temperature, a solution ofsaturated ammonium chloride (75 mL) was added followed by water (200mL). The mixture was extracted with ether (500 mL), washed with brine(100 mL), dried over magnesium sulfate, filtered and evaporated. Theresidue was dissolved in methanol (150 mL) and anhydrous potassiumcarbonate (6.0 g, 43.5 mmol) added and then stirred overnight. Thesuspension was filtered and the filtrate evaporated. The residue waspartitioned between ether (500 mL) and water (200 mL). The water wasextracted with additional ether (200 mL) and the combined ether extractswashed with brine (100 mL), dried over magnesium sulfate, filtered andevaporated to afford an orange foam. Chromatography over silica gel (150g, 40-60 μm) eluting with 25-50% ethyl acetate-hexane gave the titlecompound as a pale yellow foam. ¹H NMR δ (CDCl₃): 2.62, 3.53, 3.78,4.41, 6.36, 6.41, 7.03, 7.14-7.30, 7.39-7.47.

Step 2:3-(N-Carbobenzyloxy-3-fluoroanilin-4-yl)3-hydroxy-1-(1,1-diphenylmethyl)azetidine

To a solution of3-(4-amino-2-fluorophenyl)-3-hydroxy-1-(1,1-diphenylmethyl)azetidine(Example 81, Step 1, 5.10 g, 14.7 mmol) in acetone (75 mL) was added asolution of sodium bicarbonate (2.52 g, 30.0 mmol) in water (40 mL) togive a creamy suspension. Benzyl chloroformate (2.57 g, 15.1 mmol) wasadded and stirring continued overnight. The suspension was filtered andthe acetone evaporated. The residue was partitioned between ethylacetate (200 mL) and water (50 mL). The organic layer was washed withbrine (50 mL), dried over magnesium sulfate, filtered and evaporated toleave an amber foam. Chromatography over silica gel (150 g, 40-60 μM)eluting with 1-2% methanol-methylene chloride gave the title compound asa cream foam. HRMS: meas. 483.2087, theory 483.2084.

Step 3:N-Carbobenzyloxy-3-(N-carbobenzyloxy-3-fluoroanilin-4-yl)-3-hydroxyazetidine

Benzyl chloroformate (3.8 mL, 26.6 mmol) was added to a solution of3-(N-carbobenzyloxy-3-fluoroanilin-4-yl)-3-hydroxy-1-(1,1-diphenylmethyl)azetidine(Example 81, Step 2, 1.60 g, 3.32 mmol) in benzene (30 mL) and thenheated under reflux under nitrogen for 2 hr. The benzene was evaporatedand the residue chromatographed over silica gel (150 g, 40-60 μm)eluting with 20-60% ethyl acetate-hexane. The title compound wasobtained as a white foam. ¹H NMR δ (CDCl₃): 3.32, 4.19, 4.42, 5.08,5.17, 6.98, 7.11, 7.19, 7.24-7.43.

Step 4:N-Carbobenzyloxy-3-(N-carbobenzyloxy-3-fluoroanilin-4-yl)azetidine.

Triethylsilane (30 mL) and trifluoroacetic acid (12 mL) were added to asolution of N-carbobenzyloxy-3-(N-carbobenzyloxy-3-fluoroanilin-4yl)-3-hydroxyazetidine (Example 81, Step 3, 4.3 g, 9.55 mmol) in methylenechloride (40 mL) and stirred for 2 days. Removal of the solvents at45°/0.75 mm gave an amber oil. Chromatography over silica gel (150 g,40-60 μm) eluting with 1-3% methanol-chloroform yielded the titlecompound as a solid, m.p. 95°.

Step 5:(R)-(−)-N-Carbobenzyloxy-3-[2-fluoro-4-[5-hydroxymethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine

n-Butyllithium (5.25 mL of a 1.6 M solution in hexane, 8.40 mmol) wasadded dropwise to a stirred solution ofN-carbobenzyloxy-3-(N-carbobenzyloxy-3-fluoroanilin-4-yl)azetidine(Example 81, Step 4, 3.63 g, 8.36 mmol) at −78° under nitrogen in dryTHF (30 mL), then stirred for 2 hr. A solution of R-glycidyl butyrate(1.21 g, 8.40 mmol) in dry THF (3.0 mL) was added and the cooling bathremoved after 15 min. After 18 hr, the solvent was removed and theresidue partitioned between ethyl acetate (150 mL) and saturatedammonium chloride solution (50 mL). The organic layer was washed withwater (50 mL) and brine (50 mL), dried over magnesium sulfate, filteredand evaporated leaving an amber oil. Chromatography over silica gel (150g, 40-60 μm) eluting with 2-5% methanol-chloroform gave the titlecompound as a sticky foam. FAB-HRMS: theory 401.1513 (M+1); meas401.1521.

Step 6:(R)-(−)-N-Carbobenzyloxy-3-[2-fluoro-4-[5-[[(3-nitrophenylsulfonyl)oxy]methyl]-2-oxo-3-oxazolidinyl]phenyl]azetidine

3-Nitrobenzenesulfonyl chloride (1.70 g, 7.67 mmol) was added to an icecooled solution of(R)-(−)-N-carbobenzyloxy-3-[2-fluoro-4-[5-hydroxymethyl-2-oxo-3-oxazolidinyl]-pheny]acetidine(Example 81, Step 5, 2.79 g, 6.97 mmol) and triethylamine (1.41 g, 14.0mmol) in methylene chloride (40 mL). After 16 hr, water (50 mL) andmethylene chloride (100 mL) were added. The organic layer was washedwith brine (50 mL), dried over magnesium sulfate, filtered andevaporated. The residue was chromatographed over silica gel (150 g,40-60 μm) eluting with 25-100% ethyl acetate-hexane to give the titlecompound as a sticky foam. FAB-HRMS: theory 586.1290 (M+1); meas586.1295.

Step 7:(S)-(−)-N-Carbobenzyloxy-3-[2-fluoro-4-[5-azidomethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine

A mixture of sodium azide (1.44 g, 22.1 mmol) and(R)-(−)-N-carbobenzyloxy-3-[2-fluoro-4-[5-[[(3-nitrophenylsulfonyl)oxy]-methyl]-2-3-oxazolidinyl]phenyl]azetidine(Example 81, Step 6, 2.60 g, 4.44 mmol) in DMF (30 mL) was stirred for16 hr, then filtered. The solvent was removed at 38°/0.75 mm and theresidue extracted with ethyl acetate (100 mL) and washed with water(3×50 mL) and brine (50 mL). After drying over magnesium sulfate,filtration and evaporation gave a yellow oil. Chromatography over silicagel (150 g, 40-60 μm) eluting with 1-3% methanol-methylene chloride gavethe title compound as a pale yellow foam. FAB-HRMS: theory 426.1577(M+1); meas. 426.1580.

Step 8:(S)-(−)-Carbobenzyloxy-3-[2-fluoro-4-[5-aminomethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine

To a stirred solution of(S)-(−)-N-carbobenzyloxy-3-[2-fluoro-4-[5-azidomethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine(Example 81, Step 7, 1.63 g, 3.84 mmol) in dry THF (20 mL) was addedtriphenylphosphine (1.11 g, 4.23 mmol). After 3 hr, water (0.69 mL, 38.4mmol) was added and the reaction stirred for 2 days at which time thesolvents were evaporated. The residue was chromatographed over silicagel (150 g, 40-60 μm) eluting with 5-10% methanol-chloroform. The titlecompound was isolated as a viscous colorless oil. FAB-HRMS: theory400.1672 (M+1); meas. 400.1676.

Step 9:(S)-N-[[3-[3-Fluoro-4-[1-(carbobenzyloxy)-3-azetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Pyridine (1.0 mL), acetic anhydride (1.0 mL) and a few crystals of4-dimethylaminopyridine were added to a stirred solution of(S)-(−)-N-carbobenzyloxy-3-[2-fluoro-4-[5-aminomethyl-2-oxo-3-oxazolidinyl]phenyl]azetidine(Example 81, Step 8, 1.42 g, 3.56 mmol) in methylene chloride (30 mL),then stirred for 1 hr. The solvents were removed at 38°/0.75 mm and theresidue chromatographed over silica gel (50 g, 40-60 μm) eluting with1-2% methanol-chloroform. The title compound was isolated as a whitefoam. FAB-HRMS: theory 442.1778 (M+1); meas. 442.1777.

EXAMPLE 82(S)-N-[[3-[3-Fluoro-4-[3-azetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A solution of(S)-N-[[3-[3-fluoro-4-[1-(carbobenzyloxy)-3-azetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(Example 81, Step 9, 1.44 g, 3.26 mmol) in ethyl acetate (25 mL) andabsolute ethanol (50 mL) was added to 10% Pd/C (1.0 g) and hydrogenatedat 30 psi for 7 hr. Filtration and evaporation gave the title compoundas a white glassy solid. FAB-HRMS: theory 308.1410 (M+1); meas.308.1408.

EXAMPLE 83(S)-N-[[3-[3-Fluoro-4-[1-(carboxymethyl)-3-azetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Triethylamine (150 μL, 1.08 mmol) and methyl chloroformate (65 μL, 0.84mmol) were added to a chloroform (5 mL) suspension of(S)-N-[[3-[3-fluoro-4-[3-azetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(Example 82, 153 mg, 0.50 mmol) and stirred overnight. Additionalchloroform (25 mL) was added and the solution washed with water (15 mL)and brine (15 mL). Drying over magnesium sulfate, filtration, andevaporation gave a foam. Chromatography over silica gel (50 g, 40-60 μm)eluting with 1-3% methanol-chloroform gave the title compound as a whitesolid. FAB-HRMS: theory 366.1465 (M+1); meas. 366.1468.

EXAMPLE 84(S)-N-[[3-[3-Fluoro-4-[1-(formyl)-3-acetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

N-Formylbenzotriazole (115 mg, 0.78 mmol) was added to a stirredsuspension of(S)-N-[[3-[3-fluoro-4-[3-azetidinyl]phenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide(Example 82, 153 mg, 0.50 mmol) in THF (5 mL) and stirred overnight. Thesolvent was removed and the residue chromatographed over silica gel (50g, 40-60 μm) eluting with 2-5% methanol-chloroform to give the titlecompound as a white foam. FAB-HRMS: theory 336.1356 (M+1); meas.336.1357.

EXAMPLE 85(S)-(−)-N-[[3-[4-[1-(4-Oxo-2-thiazolinyl)-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

A mixture of(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 310 mg), methyl thiocyanatoacetate (121 mg, Bull. Chem.Soc. Jpn. 1972, 45(5), 1507) and glacial acetic acid (55 mg) in absoluteethanol (5 mL) is stirred at reflux under N₂ for 4 hrs and then cooledto ambient temperature, diluted with methylene chloride (45 mL), washedwith water (2×15 mL) and saline (20 mL), dried over anhydrous sodiumsulfate and concentrated under reduced pressure. The residue ischromatographed on silica gel (230-400 mesh, 45 g), eluting withmethanol/methylene chloride (4/96), and those fractions with anR_(f)=0.47 by TLC (methanol/chloroform, (10/90) are pooled andconcentrated to give the title compound, mp 222-224° C. (decomp.).

EXAMPLE 86(S)-(−)-N-[[3-[4-[1-(4-Oxo-2-thiazolinyl)-3,6-dihydro-2H-pyridin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 85, and making non-criticalvariations but substituting(S)-(−)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 38) for(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 209-211° C. (decomp.).

EXAMPLE 87(S)-(−)-N-[[3-[4-[1-[5-Methyl-1,3,4-thiadiazol-2-yl]-4-piperidinyl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Step 1: 2-Bromo-5-methyl-1,3,4-thiadiazole

To a solution of aqueous hydrobromic acid (48%, 40 mL) containing atrace amount of copper power at −10° C. is added a mixture of2-amino-5-methyl-1,3,4-thiadiazole (2.88 g) and sodium nitrite (7.76 g)portionwise over 45 mins with vigorous stirring. The resulting mixtureis stirred at −10° C. for 1.5 hrs and at ambient temperature for anadditional 1.5 hrs and is then cooled in an ice bath, neutralized withaqueous sodium hydroxide (50%), diluted with saturated aqueous sodiumhydrogensulfite till the mixture no longer turns potassium iodide-starchtest paper blue and filtered to remove insoluble material (rinsing withhot water). The filtrate is extracted with methylene chloride (4×100mL), and the combined organic phase is dried over anhydrous sodiumsulfate and concentrated under reduced pressure to give the crudeproduct which is then chromatographed on silica gel (70-230 mesh, 75 g),eluting with ethyl acetate/hexane (50/50). Pooling and concentration ofthose fractions with an R_(f)=0.78 by TLC (methanol/chloroform, 10/90)gives the title compound, mp 107-108° C.

Step 2:(S)-(−)-N-[[3-[4-[1-(5-Methyl-1,3,4-thiadiazol-2-yl)-3,6-dihydro-2H-pyridin-4-yl]-3-fluorophenyl]-2-oxo-5-oxaaolidinyl]methyl]acetamide

A mixture of(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 20, 550 mg), 2-bromo-5-methyl-1,3,4-thiadiazole (EXAMPLE 87,Step 1 323 mg) and potassium hydrogenphosphate (571 mg) in dimethylsulfoxide (16 mL) is stirred under N₂ at 100° C. for 2 hrs, cooled toambient temperature, diluted with water (20 mL) and extracted withmethylene chloride (3×20 mL). The combined organic phase is washed withwater (20 mL) and saline (10 mL), dried over anhydrous sodium sulfateand concentrated to give the crude product which is then chromaotgraphedon silica gel (230-400 mesh, 45 g), eluting with a gradient ofmethanol/methylene chloride (2/98-3/97). Pooling and concentration ofthose fractions with an R_(f)=0.44 by TLC (methanol/chloroform, 10/90)gives the title compound, mp 193-195° C.

EXAMPLE 88(S)-(−)-N-[[3-[4-[1-(5-Methyl-1,3,4-thiadiazol-2-yl)-3,6-dihydro-2H-pyridin-5-yl]-3-fluorophenyl]-2-oxo-5-oxazolidinyl]methyl]acetamide

Following the general procedure of EXAMPLE 87, Step 2, and makingnon-critical variations but substituting(S)-(−)-N-[[2-oxo-3-[4-(3,6-dihydro-2H-pyridin-4-yl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide(EXAMPLE 38) for(S)-(−)-N-[[2-oxo-3-[4-(4-piperidinyl)-3-fluorophenyl]-5-oxazolidinyl]methyl]acetamide,the title compound is obtained, mp 229-231° C. (decomp.).

We claim:
 1. A process for the preparation of a compound of formula I:

or a pharmaceutical acceptable salt thereof wherein: X is —NR₁—,—S(O)_(g)—, or —O—; R₁ is —H, C₁₋₆ alkyl, optionally substituted withone or more —OH, —CN or halo, —(CH₂)_(h)-aryl, —COR₁₋₁, —COOR₁₋₂,—CO—(CH₂)_(h)—COR₁₋₁, —SO₂-C₁₋₆ alkyl, —SO₂CH₂-aryl, or —(CO)_(i)-Het;R₁₋₁ is —H, C₁₋₆ alkyl, optionally substituted with one or more —OH, —CNor halo, —(CH₂)_(h)-aryl, or —(CH₂)_(h)—OR₁₋₃; R₁₋₂ is C₁₋₆ alkyl,optionally substituted with one or more OH, CN or halo, —(CH₂)_(h)-aryl,or —(CH₂)_(h)—OR₁₋₃; R₁₋₃ is —H, C₁₋₆ alkyl, —(CH₂)_(h)-aryl, or—CO(C₁₋₆ alkyl); R₂ is —H, C₁₋₆ alkyl, —(CH₂)_(h)-aryl, or halo; R₃ andR₄ are independently —H or halo; R₅ is —H, C₁₋₁₂ alkyl, optionallysubstituted with one or more halo, C₃₋₁₂ cycloalkyl, C₁₋₆ alkoxy; arylis a phenyl, pyridyl or naphthyl moiety, optionally substituted with oneor more —F, —Cl, —Br, —I, —OH, —SH, C₁₋₆ alkyl, or C₁₋₆ alkoxy; Het is5, 6, or 9 membered heterocyclic rings having one to three O, N and Satom; g is 0, 1 or 2; h is 1,2, 3 or 4; i is 0 or 1; m is 0, 1, or 2; nis 0, 1, or 2; the fotted line ——— is a single or double bond; and withthe proviso that m and n taken together are 1, or 2; which comprises: a)introducing —C(═O)R₅ or —C(═O)R₅₋₁ into the amino group of a compound ofthe formula II;

b) when X₁ is a protected X in formula III, deprotecting the protectinggroup by catalytic hydrogenation of a compound of formula III;

c) when ——— is a single bond, catalytically hydrogenating a compound offormula I; d) when ——— is a double bond, eliminating an element of waterfrom a compound of formula IV;

e) when X is NR₁ and R₁ is —COR₁₋₁, —COOR₁₋₂, —CO—(CH₂)_(h)—COR₁₋₁,—SO₂-C₁₋₆ alkyl, —SO₂CH₂-aryl, or —(CO)-Het, reacting a compound offormula V

with L—COR₁₋₁, L—COOR₁₋₂, L—CO—(CH₂)_(h)—COR₁₋₁, L—SO₂—C₁₋₆ alkyl,L—SO₂CH₂-aryl, or L—(CO)_(i)-Het; wherein X₁ is X or protected X; R₅₋₁is R₅ or protected R₅; R₁, R₁₋₁, R₁₋₂, R₂, R₃, R₄, R₅, aryl, Het, X and——— are as defined above, L is a leaving group; and f) thereafter, ifnecessary, removing any protecting groups.
 2. A process for preparing acompound of structure 17 which comprises: a) treating a compound ofstructure 7 with ethyl cyanoacetate in the presence of an appropriatebase following by alkylation to provide a compound of structure 8; b)reducing structure 8 to give amino-aniline 9; c) treating 9 with anappropriate base to provide a lactam 10; d) reducing 10 by using anappropriate reducing agent to provide azetidine 11; e) reacting 11 withbenzyl chloroformate to provide benzyl carbamate derivatives 12; f)treating 12 with n-butyllithium in an appropriate solvent, followed byaddition of (R)-glycidyl butyrate to provide oxazolidinone 13 inenantiomerically enriched form at the 5-position of the oxazolidinonering; g) converting 13 to the corresponding alkyl or aryl sulfonate 14by treatment with alkyl or aryl sulfonyl chloride in the presence oftriethylamine or pyridine; h) treating 14 with an alkali metal azidesuch as sodium or potassium azide with an optional catalyst to affordazide derivatives; i) reducing the azide derivatives to thecorresponding amine 15 by hydrogenation in the presence of a palladium,platinum or nickel catalyst in an appropriate solvent, or alternatively,preparing amine 15 by treating 14 with an appropriate solvent which issaturated with ammonia and heating the mixture to 100° C. in a sealedtube; j) acylating 15 with an acid chloride or anhydride in the presenceof a base such as pyridine or triethylamine at temperature ranging from−40° C. to 40° C. to provide the N-acyl oxazolidinone 16; and k)catalytic hydrogenation of 16 in the presence of a noble metal catalystto provide the azetidine 17;

wherein R₂, R₃, R₄ and R₅ are as defined in claim
 1. 3. A process forpreparing a compound of structure 17-b which comprises:

a) reacting a compound of structure 18 with a protected aniline 19 inthe presence of an appropriate base to afford compounds 20; b) reacting20 with benzyl chloroformate at about 0° C. to about 25° C. to provide acompound of structure 21; c) reacting 21 further with benzylchloroformate at about 25° C. to about 100° C. to provide compound 22;d) treating 22 with excess triethylsilane and trifluoroacetic acid in asuitable solvent to provide compound of structure 23; and c) performingthe steps of (f) to (k) as shown in claim 2 to provide a compound ofstructure 17-b; wherein R₃, R₄ and R₅ are as defined in claim
 1. 4. Aprocess for preparing a compound of structure 28 which comprises: a)coupling of vinyltributyltin 24 and compound 25 to provide a compound ofstructure 26; b) treating 26 with a solution ofN-benzyl-N-(methoxymethyl)trimethylsilylmethylamine and trifluoroaceticacid in an appropriate solvent to provide 27; and c) removing theN-benzyl group of 27 by catalytic hydrogenation in the presence of anoble metal catalyst to provide a compound of structure 28;

wherein R₃, R₄ and R₅ are as defined in claim
 1. 5. A process forpreparing a compound of structure 28 which comprises: a) reacting acompound of structure 7 with dimethylmalonate to provide a compound ofstructure 29; b) alkylating 29 to provide nitrile 30; c) reducing 30catalytically in the presence of a palladium, platinum or nickelcatalyst, in an appropriate solvent, to provide a compound of structure31; d) decarboxylating 31 to provide 32, which upon reduction with anappropriate reducing agent to affords compound 33; and e) performing thesteps of (e) to (k) as shown in claim 2 to provide a compound ofstructure 28;

wherein R₃, R₄ and R₅ are as defined in claim
 1. 6. A process forpreparing a compound of structure 40 or 41 which comprises:

a) reacting a compound of structure 35 with a protected aniline 19 inthe presence of an appropriate base to provide compounds of structure36; b) reacting 36 with benzyl chloroformate to provide compound 37; c)eliminating a element of water to provide regiosiomers 38 and 39 as amixture; e) performing the steps of (f) to (k) as shown in claim 2 toprovides compounds 40 and 41 as a mixture; and f) where X is S,oxidizing the sulfur atom with an appropriate oxidizing agent to providethe corresponding sulfones and sulfoxides, respectively; wherein X is Oor S; R₃, R₄ and R₅ are as defined in claim 1.